He does it thrice. The first time is just prior to the famous bridge scene where he had stayed behind briefly to magically seal a door. The Balrog broke the spell but collapsed the roof, forcing it to go the long way to catch up. The third time, he prevents the Witch-king from riding into Minas Tirith when the main gate is breached, with a completely still "You cannot enter here." This doesn't culminate in a duel since just at this moment, the Rohan reinforcements arrive. A similar scene is included in the extended version of the Return of the King film. Pity he loses this one.
Amusingly, in the first draft of Gandalf's confrontation with the Witch-king, he actually says "You cannot pass" (the same thing he said to the Balrog); but Tolkien changed it to "You cannot enter here", presumably to avoid being too obviously repetitive.
Dernhelm's ( a.k.a. Éowyn's) defense of Théoden against the Lord of the Nazgûl: "Do what you will; but I will hinder it, if I may." She even laughs at him.
"For living or dark undead, I will smite you, if you touch him!"
Boromir telling the hobbits to flee and then building himself a funeral mound of orcish corpses probably qualifies as well.
During the War of the Rings, the townfolk of Dale retreat into the Lonely Mountain as Sauron's armies approach. King Brand of Dale is killed during the battle. The Dwarf-King Dain II Ironfoot stood astride his friend's body and held the enemy back until he also falls.
Beregond leaves his post in order to pull one of these to stop Denethor from succeeding in lighting Faramir's pyre.
Gondor as a whole does this. For thousands of years they were what was keeping Sauron's forces at bay.
There are so many instances of this in The Silmarillion that one can safely conclude Tolkien loved this trope.
Húrin, the father of Túrin Turambar, pulls this off against the entire army of Morgoth alone so his allies can escape. He fights to the point where his axe melts in his hands and even then does not give up. All the while shouting: "Day shall come again."
Finrod Felagund breaks out of his chains and kills a Werewolf barehanded to save Beren.
Huan, the hound of Valinor, stands up against Carcaroth, the mightiest werewolf who has a Silmaril in its body, in order to protect Beren. Huan manages to slay the crazed werewolf before succumbing to wounds but Beren dies nonetheless. This only occurs because Beren was trying to protect Lúthien against Carcharoth in yet another invocation of this trope. Waving a Silmaril in a badass werewolf's face will cost you your hand, however.
During the sack of Gondolin, Ecthelion, a high-elf lord, defends a wounded Tuor against Morgoth's chief captain Gothmog. Ecthelion manages to take down the Balrog before he dies, after losing both his armsnote In case you're wondering, he kills it with the spike on his helmet. Glorfindel also killed a Balrog (and was killed) while the survivors were fleeing in the mountains.
Subverted during the Flight of the Noldor when Fëanor is leading his people from Tirion. A messenger from Manwë appears and tries to oppose their departure (into certain death no less), but Fëanor is the more powerful in voice of the two and convinces them to depart all the same: "In that hour the voice of Fëanor grew so great and potent that even the herald of the Valar bowed before him as one full-answered, and departed; and the Noldor were over-ruled."
Parodied in Bored of the Rings when the Fellowship actively chop down the rope bridge with Goodgulf and the Ballhog on it.
The event referenced in one of the Vlad Taltos books where Sethra Lavode compares the tactics of defense to being a real estate agent (i.e. get as high a price as possible for any ground lost) to her apprentice, Sethra the Younger. In a battle a few days later, Sethra the Younger offers to retreat from her strategically-important pass if the enemy commander will send a third of his force, unarmed, through to the prison camps behind her lines. He refuses, and gets his behind handed to him in the ensuing assault.
In Robert Jordan's The Great Hunt, Ingtar, having been revealed as a Darkfriend, redeems himself by holding off the advancing Seanchan at the cost of his life, allowing Rand and his compatriots to escape.
An awesome example in the Breaking: When Jaric Mondoran, a maddened sorceror with the power to devastate whole districts, approaches Tzora the Da'shain went to meet him, ten thousand of them, and began to sing to remind him what he once was, and give the (at least) hundreds of thousands of people living in Tzora time to escape. He looked at them puzzled while burning them alive one by one. They closed their ranks and kept singing. He listened to the last one for over an hour. After that the second largest city in the world burned, leaving only a sheet of glass.
In the Star Wars Expanded Universe novel Rogue Squadron, Rogue Squadron and Defender Wing are ambushed by a type of capital ship designed to slaughter large numbers of starfighters. With a little cleverness, Corran Horn works out a scenario to distract, damage, or destroy it it so that the others can get away — "Worst case, you lose one ship." Not only did it work, Horn and his ship survived.
It happens again later in the series. When Rogue Squadron is lead into a deathtrap at Distna, One and Two flight (eight X-wings) are forced to fight three squadrons of enemy fighters, while Three flight is forced to take on the same number (with half as many ships) so that the others can attempt to escape. "Alright three flight, we're holding the door open." Delaying Actions are standard for the Rogues; they pull one in The Thrawn Trilogy and are only saved when the cavalry returns.
In the Star Wars: New Jedi Order novel Traitor, the Jedi Ganner Rhysode declares, "I am Ganner. This thresholdnote the entrance to the Well of the World Brain is mine. I claim it as my own. Bring on your thousands, one at a time or all in a rush. I don't give a damn. None shall pass." and proceeds to slaughter hundreds of enemy warriors before being overcome, buying time for Jacen Solo. When he's finally overwhelmed, he pulls a Samson by collapsing the (large) building he's in on both himself and his foes (which included a tank). In fact he was so damn impressive that, according to an Unreliable Narrator, in the future he would be made into a deity in the enemies' pantheon called "The Ganner", an invincible giant armed with a sword of light, guarding the gate to the world of the dead, upon which is inscribed — in Basic, not Yuuzhan Vong — NONE SHALL PASS.
In Legacy of the Force, Wedge Antilles has to scramble for impromptu designations for himself and Corran. Since they're flying a delaying action, he chooses Ganner One and Ganner Two. What could be more appropriate?
Death Star has the Force-Sensitive stormtrooper Nova Stihl repeatedly Dreaming of Things to Come, and one dream is of he and one other fighting off his fellow stormtroopers, and dying, while trying to buy time for others. He manages to avoid something from another dream, but for this one, he goes along with it and delays the other stormtroopers long enough that his little cell of Imperials going through a Heel Realization can escape. He is assisted in this by another alien, who was a bar bouncer.
In the novels, having Harrington go into battle in a seriously outmatched ship with practically no possibility of victory and massive casualties happened frequently enough in the early books that an "Honor Death-Ride" has become cliche (and to be fair, is noted by various characters in the books themselves such as in Honor Among Enemies when several crewmen, upon finding out who's commanding their new ship, immediately begin figuring out how to desert before the inevitable catastrophic battle).
Of course, the ones doing that are dirtbags that their former commanders couldn't wait to be rid of. Their eventual fate was a rather more literal variety of Laser-Guided Karma. Or, in this particular case, graser guided karma.
Edward Saganami's You Shall Not Pass! moment got Manticore's version of the US Naval Academy in Annapolis named after him. They also show his final battle to the graduating class every year.
Honor's armsmen live (or rather, die) for this trope. Given the number of people that try to kill her, Honor gets through rather a lot of them, much to her regret.
The Home Fleet in the Battle of Manticore, buying time so the Eighth Fleet can close the distance to engage the invading Havenite fleet.
Also by David Weber in the Hell's Gate series you have "Chunika s'hari, Halian. Sho warak", or "I am your son, Halian. I remember." Archaic words said by the Imperial family when invoking their precognition. It takes only 20 years to make an emperor, but 20 centuries to make an empire the world can trust. For many members of the family, their precognition is weak except in the circumstances of their immediate death. For them to make this proclamation means they will die in their actions, but their death will hold the line.
In Mercedes Lackey's and James Mallory's The Obsidian Trilogy, and specifically the first book, The Outstretched Shadow, Jermayan tells Kellen the story of five scouts from the last war with the Endarkened, who held an entire demon army in a narrow pass for three days, buying time for the allied armies to gather. "History" lost their names (even though there are elves living who are so old they are no more than two generations from the time of the last war, thousands of years ago), and it's not known how they did it, but their sacrifice is remembered.
The song "Demonsbane" is about Vanyel doing this to protect some Hardornen farmers. The line "You shall not pass" is used twice in the song.
So did Lavan, though his particular explosion was more out of rage, grief, and a sudden lack of desire to live. Maybe more Taking You with Me?
There is a specific spell called Final Strike which any magic-user, even an apprentice can use which sucks in all the ambient magical energy of the area and channels it through the spell-wielder's body; it will fry you, but the resultant explosion will take your opponent with you—and, depending on how big the explosion, anything within a certain radius. The higher-level magic user you are, the bigger the explosion.
In the old pre-revision Magic: The Gathering novels, a Viking-ish female captain (a lesbian with two wives, no less) named Ordando faces down cavalry in an alleyway to buy time for the general of her army and the rest of their small infiltration party to escape.
In Fall of Damnos, Largo and Brakkius do this to the Necrons, deciding to sacrifice themself to cover the retreat of the rest of their squad. Subverted when Tigurius jumps in and blows the Flayed ones to the Warp and beyond.
In the original Dune book, Duncan Idaho sacrifices himself to hold off a flood of Imperial Sardaukar elite troopers, while Paul Atreides makes good his escape. In the sequel, it's revealed that while he did, indeed, die, the surviving Sardaukar were so impressed with his Master Swordsman skills that they preserved his body, later having it resurrected as a "Ghola"... and that, as it turns out, has some extremely far-reaching effects on the Dune universe.
In Jim Butcher's Codex Alera novel Cursor's Fury, the hero, Tavi, has to hold a bridge against a massive invading army with an inexperienced, under-equipped, and badly-outnumbered Legion (6 thousand Legionnaires against sixty thousand invaders). He very nearly has to sacrifice himself and a cohort of his legionares to hold off the invaders, and although he survives, the fact that he actually declares, "You will not pass," to the leader of the invading army makes it worth mentioning as an example.
A massive invading army of eight-foot-tall berserker wolf-men, which simply adds a whole 'nother level of badassery to the act.
And the fact that he pulls it off and manages to send them into retreat makes it all the more impressive.
In Harry Potter, there's a charm that works just like this. If you protect someone with strong will, and die for them, then your sacrifice will fuel a charm — making your protected ones completely immune from direct harm from the one that killed you. That's how Harry survived the Death Spell from Voldemort (by having his mother inadvertently cast this charm), and later, in the last book, how Voldemort's curse became ineffective against Hogwarts' students (by Harry's Heroic Sacrifice).
Also Bragoon the otter and Sarobando the squirrel from Loamhedge, similar to Gandalf's example, threw a log that was bridging a canyon down said canyon while foes were scrambling across it, to save the three young ones that were with them. Being pretty old, they died of exhaustion shortly afterward.
Also also, Felldoh the squirrel in Martin the Warrior was probably the first example of this in the writing of the books. He takes down at least twenty enemies and scares the rest enough that after he's dead, the rats are talking about later basically saying "thank GOD we didn't get to him in time!"
In the Wing Commander novel "Fleet Action", a vastly outnumbered and outgunned Confederation manages to hold off the Kilrathi fleet, at one point having civilian craft play "human shield" for the Marine landing craft to board the Hakaga supercarriers, to detonate antimatter mines from the inside, where the heavy armor not only didn't help the Hakagas, but helped focus the blast to gut the ships from the inside.
"Gunny" Pappas, in When the Devil Dances, holding off the Posleen, and the ACS troopers who were too damaged to move did this, while the rest of the force retreated for resupply.
In William King's novel Space Wolf, Sergeant Hengist rallies a group of young Marines about him to hold off attacks from Chaos Space Marines, sending off a handful, led by Ragnar, to Bring News Back. When a Chaos Space Marine tell Ragnar that the group had broken and the Chaos Space Marines were hunting them down, Ragnor refuses to believe him.
In Lee Lightner's Wolf's Honour, two veteran units hold off the rebel attack long enough for the rest of the Imperial Guard to reach the fortified perimeter; they die to the last man.
In James Swallow's novel Red Fury, all the sons of Sanguinius throw themselves into defending the tomb of Sanguinius, knowing that if they fail, the survivors' only choice will be to be destroy the fortress.
In Henry Zhou's novel The Emperor's Mercy, Imperial Guardsmen are surrounded by Chaos forces and are fighting on, despite dying of hunger and disease. Roth tells Celemine that they had no choice but to stay with them. The commander hears and instantly wants to fight a last charge: they can get them to their ship and hold off the enemy — and that way, they can be remembered. (They are. In fact, their eighteen minutes defense of the ship is immortalized in a mural on Terra.)
In John French's Ahriman: Exile, Thidias manages to hold off an endless tide of daemons just long enough for Astraeos and Ahriman to reach their shuttle and escape, and he kills quite a few of them before finally being brought down.
In Raymond Feist's Darkness at Sethanon, Laurie's friend Roald holds off approaching Dark Elves after he breaks his leg in a fall. He tells his friend to "Make a song about me, Make it a good one", before he gives a decent accounting of himself, allowing his friends to escape.
When Zhang Xiu ambushed Cao Cao, Dian Wei remained behind to hold the main gate against Zhang's forces. Because his usual weapon was stolen, Dian Wei instead used a normal infantryman's sword until it broke, at which point he used a pair of normal infantrymen. Not surprisingly, even after he died the enemy were still terrified of passing the main gate.
A warrior named Zhang Fei managed to pull this off single handedly against an entire army. It was a bit different, though, as there was no actual fighting, just a very tense stand-off where the opposing commander Cao Cao was so taken aback by the audacity of a single person trying to hold off an army, that he figured that it was an attempt to lure him into a trap. Once Zhang Fei yelled, however, all bets were off, and the entire army... ran away. Ironically, Zhang Fei had a bunch of followers raising clouds of dust to make it look like an ambush would be waiting if Cao Cao's army advanced, although it's shown that while the advance elements was stalled by that 'poorly disguised ambush' it was Zhang Fei himself that scared Cao Cao.
Not to forget Zhuge Liang, who single-handedly held off Sima Yi's army with an empty city and his own reputation.
Bigwig: "My Chief Rabbit has told me to defend this run, and until he says otherwise, I shall stay here."
This doubles as a Badass Boast by proxy; the attacking rabbits, accustomed to a hierarchy of physical force, conclude that Bigwig's Chief Rabbit must be even bigger and badder than he is. They are appropriately shaken, although Bigwig is quite unaware of it.
A Thanatos Gambit as well: Bigwig figures that even after they kill him, they'll have to dig around his corpse.
In World War Z, a man relates the story of how the zombie war went down in Paris, including how his brother's unit attempted to contain the inmates of an insane asylum that had been zombified:
One squad against three hundred zombies. One squad led by my baby brother. The last thing we heard before the radio went silent was his voice on the radio: "They shall not pass!"
Kurt's death in Halo: Ghosts of Onyx counts as this. He holds off Covenant forces long enough for the Slipspace portal on Onyx to close thus saving the other Spartans and Dr. Halsey. This also leads to his Crowning Moment of Awesome:
Voro 'Mantakree: One last fight Demon. You shall die, and we will reopen the silver path. Kurt Ambrose:(laughs) Die? Didn't you know? Spartans never die. (detonates FENRIS nuclear warhead)
In Toby Frosts third Space Captain Smith book, Wrath of the Lemming men, Agshad nine-swords single-handedly wins the battle of Tam Valley, defending the bridge from an army of bloodthirsy Yullian soldiers using only his broom before he is finally felled by a sneak attack from Colonel Vok.
Done twice in the web original The Salvation War. The first, in Armaggeddon??? has a group of retired Chinese soldiers using bolt action rifles and then bayonets, to hold off a demon from slaughtering the women and children of their town. The second is in Pantheocide when a Palestinian suicide bomber takes his jeep full of explosives to attack The Scarlet Beast and the Whore of Babylon as they ravage Jerusalem. Limited in its success, it's still the first thing that actually hurts them... When he arrives in Hell (everyone goes there), several women offer themselves to him.
The Swedish-language Finnish poem The Tales of Ensign Stål contains a classic and rather interesting example of this. The poem at one point tells the story of the brave but incredibly stupid soldier Sven Dufva who, in the middle of a battle against the Russians during the Finnish War (1808-1809) misunderstands an order to retreat and instead attacks the enemies in front of him. He singlehandedly manages to hold a bridge until reinforcements can arrive, sacrificing his life in the process.
The quote "Släpp ingen djävul över bron" (in modern English roughly "Don't let a single fucker cross that bridge") has been a go-to phrase in Swedish for holding out against overwhelming odds ever since. Though the bit about simply being too stupid to retreat usually gets left out.
Umslopogaas dies defending a staircase against a small army at the climax of Allan Quatermain.
A bit of Back Story in one of Andre Norton's Alternate History books, The Crossroads of Time, mentions that after World War II went really, really bad for the Allies, and "Japs exploded all over the Pacific," the last word the U.S. got from Australia was that "they were still fighting a desperate rear guard action along the salt deserts there...." That was in late 1940 or early '41; the hero gets this information something like ten or fifteen years later.
This is how Elven Hunter Crispin goes out in The Elfstones Of Shannara. With all his companions dead, Crispin holds the bridge at the Pykon against The Reaper, a Demonic Serial Killer in order to give Wil and Amberle time to destroy the bridge. Easily his Dying Moment of Awesome.
Almost all of Jair's companions in The Wishsong of Shannara die this way, staying behind one or two at a time to delay the Gnomes and other enemies that are chasing them.
Alexandre Dumas' The Vicomte de Bragelonne: Ten Years Later. Porthos destroys the tunnel network that he and Aramis are using to plot a rebellion against the King of France, buying Aramis and the rebels enough time to escape and destroying most of their pursuers.
Done against an object, but otherwise the same in Distant Rainbow by Strugatski brothers. When the Wave suddenly overpowers most of "Charibdas" (wave-stopping machines), causing them to explode and starts advancing rapidly at the scienific outpost, Robert takes one of the two remaining Charibdas and steers it against the Wave so the other scientists can evacuate. He escapes the machine seconds before it blows up, along with Patrick, who steered the other one.
Talenel'Elin, one of the ten Heralds of the Almighty, was known for doing this. He had a habit of choosing narrow passes that couldn't possibly be defended, defending them, and dying in the process. His death sent him back to Damnation, where he was tortured until the next Desolation came and he would be resurrected along with the rest of the Heralds. Except at the Last Desolation, the other nine Heralds gave up and abandoned him to be tortured alone. He returns at the end of the first book four and a half thousand years later, signaling that the next Desolation has come.
Kaladin Stormblessed does this against an army of Parshendi at the end of the first book to save Dalinar Kholin, the last honorable highprince left in the entire Alethi army. It is easily the best battle scene in the entire book. The best part? Kaladin lives and gets his freedom.
A Game of Thrones. Syrio Forel holds off five Lannister guardsmen and a knight of the Kingsguard with only a wooden sword to buy time for Arya Stark to flee. He actually kills the lightly armored Lannister guards, and is only defeated by the knight in heavy armor and full helmet.
A Storm of Swords has Squire Dalbridge pull this on the Wildings to help Stonesnake, Ebben, Jon Snow and Qhorin Halfhand escape.
In A Dance with Dragons, Theon is fleeing Winterfell with some wildling women and Jeyne Poole. Once their stealth is broken, one of his companions, Frenya, a spearwife, stays behind to stop the guards while the others flee. We never see what happens to her at the end, but it is strongly implied that she is killed. However the trope is subverted when the others realise that Frenya still has the rope they were going to use to climb down the castle wall.
Moat Cailin and the Crannogmen play this role to the North, being located in the Neck, which separates the North from the Southron Kingdoms. Moat Cailin is on the only safe path through the Neck, and can be easily held by a small force against a much larger army from the south, having never fallen to the Southron forces.
The fight at the Tower of Joy consisted of this. Ned Stark and six companions went to the Tower of Joy to rescue Ned's sister Lyanna, who had been kidnapped (allegedly) by Prince Rhaegar Targaryen, but found the Tower guarded by three of the Kingsguard. In the battle all were killed save Ned and his bannerman Howland Reed. Exactly why the Kingsguard remained guarding Lyanna is unclear, considering Rhaegar and his father King Aerys II were dead. It is widely believed by the fandom Lyanna was pregnant with Rhaegar's child, and the Kingsguard were guarding the future Prince.
The Night's Watch mans the Wall which separates the Seven Kingdoms from the Northernmost part of Westeros, the Lands-beyond-the-Wall. They were apparently formed 8000 years ago when the Wall was built, to defend the realms against the White Walkers, though have spent most of their time fighting the Wildlings (people who live North-of-the-Wall), and are seen as a glorified Penal Colony by much of Westeros.
John Geary's claim to fame in John Hemry's The Lost Fleet. Taking on enemy ships, outnumbered ten to one, so the ships he was escorting could escape immortalized him in The Alliance.
This is how Rastar Komas Ta'Norton, last Prince of fallen Therdan, meets his end in the final book of the Prince Roger series.
The poem "Horatius" by Thomas Babington Macaulay sets the Roman legend (see the Real Life section) into English verse, in words that readily define the trope. In the poem, Horatius proposes to hold a bridge against an army while the village he's defending cuts it down behind him:
‘Hew down the bridge, Sir Consul, With all the speed ye may; I, with two more to help me, Will hold the foe in play. In yon strait path a thousand May well be stopped by three. Now who will stand on either hand, And keep the bridge with me?’
Warcraft Expanded Universe. The War Of The Ancients novels give us one of the greatest examples in the entire Warcraft universe. Broxigar, an orc transported back in time, leapt through a portal that lead to the Burning Legion homeworld. Once there, he proceeded to slaughter demons until he stood upon a mountain of their corpses, to the point that Sargeras himself had to kill him, but not before Brox did the impossible and wounded him. All of this with an axe made of enchanted wood.
The first chapter of Star Trek: Ship of the Line, has the USS Bozeman, a Soyuz-class border cutter, being left alone in a sector bordering the Klingon Empire, while the Enterprise and most of the fleet is sent to face off the Klingon fleet threatening to invade. While on patrol, the Bozeman detects a Klingon heavy cruiser sneaking across the border in order to destroy the Federation outpost there. While no match for the Klingon warship, the small border cutter decides to do everything possible to hold off the Klingons and let the rest of the fleet know what's going on. They launch a probe with a time-delayed message set to transmit after exiting the Klingon ship's jamming field, while the Bozeman maneuvers trying to avoid the heavy disruptor shots. It helps that the commanders of the ships are old rivals, so Captain Bateson is able to goad Kozara into attacking him instead of making a beeline for the outpost. Desperate, the Bozeman attempts to hide in a small nebula, only to emerge 100 years later nearly colliding with the USS Enterprise-D (TNG episode "Cause and Effect"). They later find out that they are remembered as heroes for thwarting Kozara's attempt. Their message reached the fleet, and the original Enterprise was able to drive the Klingon ship away. Kozara, still alive, has been living in shame for his failure since then, and the shame is only increased when it's discovered that the Bozeman survived. Naturally, he plots revenge.
A Mage's Power: Basilard pulls this in the Yacian Caverns in order to enable his students and client to escape a pack of Xethras. He survives, barely, because Aio pulled him to Nolien, The Medic. Then Tasio reveals that neither one of them were in true danger beacuse it was All According to Plan.
In Jeramey Kraatz's The Cloak Society, Guardian and Sentry fight Ghost to keep him from preventing the others' escape, and escaping himself, from the Gloom.
In the third book of the Inda series, the Venn are invading and the king's armies are not yet in position, due to several key messages about the enemies' whereabouts being intercepted. This leaves a little under two hundred women and girls to defend Castle Andahi, which covers the only passage through the mountains. They hold it against several thousand Venn for almost three full days.
Alexis Carew: The Little Ships: Faced with a Hanoverian frigate blowing up the eponymous unarmed evacuation ships, Alexis plants her horribly outmatched barque Belial in its path and provokes it by signaling that the captain is a coward and an arschfickernote "ass-fucker" in German. In the ensuing broadside duel her ship is damaged beyond repair and most of the crew and passengers are killed, but the other ships get away, and purely by chance she manages to kill the enemy captain and first lieutenant, and the frigate ends up surrendering to her instead!
In Warrior Cats, Cinderpelt (a Medicine Cat with a lame leg) places herself between Sorreltail with her newborn kits and the badger that has just burst into the den. The badger end up killing her, but she manages to hold it off long enough for Leafpool and Crowfeather to arrive and drive it off, ensuring that Sorreltail and all of her kits survive the attack.
The Divine Comedy, specifically Virgil in Purgatorio Canto 18, figures reason as a lone guard fighting off evil desires and thoughts from entering the threshold of the mind with all his might.