Julius Caesar: In the climatic "Friends, Romans and Countrymen" speech by Mark Antony, Shakespeare has a clever balancing act of dramatic tension; Antony has pretended to not seek retribution against Caesar's murderers, and his speech follows one by Brutus in which the people of Rome were convinced that killing Caesar was necessary. Antony's speech utilises the phrase "But Brutus says that Caesar was ambitious, and Brutus is an honourable man". At first he appears to be in agreement with the conspirators; but his speech gradually begins to demonstrate the holes in their logic, and his repetition of the phrase "honourable man" becomes sarcastic, and then insulting.
Shakespeare later parodied this in Measure For Measure, where a character prone to getting his words mixed up tells a criminal "Prove it before these [criminals], thou honourable man!".
Wicked: "As someone told me lately, everyone deserves the chance to fly!"
And the song "I'm Not That Girl". First act, Elphaba sings it, but in the second, Glinda does.
"It is my personal opinion that you do not have what it takes. I hope you'll prove me wrong. I doubt you will." Madame Morrible allows Galinda to join the sorcery seminar at Shiz. Years later, Glinda allows the guards to take Madame Morrible to prison.
Elphaba, in The Wizard and I desires a "celebration throughout Oz that's all to do with me." Later, the Wizard says that she'll have a "celebration throughout Oz that's all to do with you." This proves true when the Munchkins celebrate her death.
The first scene and the last scene. They're exactly the same scene, but the first is told from the Munchkins' point of view and the second is told from Glinda's point of view, with the appropriate changes in emphasis and tone. In the latter, the Munchkins continue to chant "No One Mourns the Wicked" while Glinda laments.
Elphaba refuses to believe Fiyero when he tells her that she's beautiful—he insists "it's not lying, it's seeing things in a different way". Elphaba uses the line on Fiyero after he turns into the scarecrow.
Common in older theatrical writing, particularly in the Victorian period. Gilbert and Sullivan's The Yeomen of the Guard has a lot of this, the most obvious being the repeat of "I have a Song to Sing-O", first as Jack and Elsie working together to entertain a crowd as street performers, and then at Elsie's wedding to Fairfax, as him trying to win her back, and her rejecting him, as gently as she can, with the only change in lyrics making it worse, by indicating the rest of the story the song tells, where the jester gets the woman back, will not follow. However, that's only the most obvious; lines bounce around characters and situations throughout the work, reflecting ironically on the changing circumstances.
There was a barber and his wife, and she was beautiful... - the first time Todd is mourning the wife he was forced to leave behind. The second time he's still mourning... having just realised that he's responsible for her death.
Eminently practical and yet appropriate as always... - first time a genuine compliment from Todd to Mrs Lovett, regarding her idea of making his victims into pies. The second time he's trying to get her guard down...
Used in Les MisÚrables, which uses identical melodies rather than lyrics for many of its songs. For example, "Valjean's Soliloquy" is a triumphant tune that culminates in him resolving to turn his life around . . .while "Javert's Soliloquy" is a mournful, distressed one that culminates in his suicide.
The two songs mentioned above even use some identical lines in the coda, with the differences providing the contrast:
I am reaching, but I fall,
(second line different: And the night is closing in,/And the stars are black and cold,)
As I stare into the Void,
(third line different: To the whirlpool of my sin./To a world that cannot hold.)
A somewhat subtle example — the line "Jean Valjean is nothing now" can also be seen as this. It first appears in "Valjean's Soliloquy" when Valjean resolves to forsake his old identity and become a better man. In "Confrontation," it's sung by Javert after he has learned that the mayor he's been serving is actually Valjean, a convict who has broken his parole and whom Javert has resolved to capture.
And another one - at the barricade, Valjean prays for Marius to survive, asking God to "Bring him home." Later on, when Valjean feels that his life is all wrapped up and he's ready to die his prayer is similar, but changes to "Bring me home".
Then there's "Little People". This song introduces Gavroche as a bright, upbeat sort of kid who has a lot of potential. Its reprise is one of the biggest tearjerkers in the whole play: the rebels are running low on ammo, and Gavroche goes out to loot some from the dead soldiers, singing this song as a sort of Determinator mantra despite being shot repeatedly. He doesn't even finish the song.
The Phantom of the Opera uses both identical melodies and lyrics. "All I Ask Of You" is a joyous love song between Christine and Raoul, but when the Phantom sings it to Christine, it's a desperate plea for her love. And most notably, the final lines of "Music of the Night", "You alone can make my song take flight, help me make the music of the night", are a passionate declaration of love, but when the Phantom sings them at the end of the show, he is now despairing of having lost Christine. "It's over now, the music of the night."
In Miss Saigon, Chris asks Kim, "How in the light of one night did we come so far?", as they fall madly in love and spend the night together. But at the end of the show, as she lies dying in his arms, she asks him the question ("How in one night have we come... so far?"), but this time, it's mourning their lost chance at happiness.
In South Pacific, "Younger Than Springtime" initially describes Joe Cable's newfound love for Liat. But after he refuses to marry her (unwilling to confront the prejudice they would face as an interracial couple), the song's reprise now represents the end of their relationship.
In Under Milkwood, we hear that Bessie Bighead puts flowers on the grave of Gomer Owen who "kissed her once by the pigsty when she wasn't lookin, but never kissed her again although she was looking all the time." That line gets a laugh. Later on, after we learn that Bessie has Down Syndrome or something of the sort, and that Gomer kissed her because he was dared, when the same line comes back it isn't so funny.
In classical playwright Aristophanes' comedy Clouds, when the antihero Strepsiades asks why Socrates is suspended in the air, the philosopher responds: 'I am walking in the air, and speculating about the heavens.' After Strepsiades gets fed up with the sophistic prattling of the philosopher, he climbs to the roof of his academy and starts to burn it down. When Socrates, in a panic, demands to know what he's doing on his roof, Strepsiades parrots back: 'I am walking in the air, and speculating about the heavens!'
The reprise of Somewhere That's Green in Little Shop of Horrors, cut from the film. The song originally was about the happy, quiet life of the suburbs that Audrey thought of as heavenly, with only the barest references to Seymour's love of plants. In the reprise, she's dying, and all that's left of her dream is to be with Seymour, somewhere that's green: in the man-eating plant that killed her.
Vanities: The Musical: During "The Argument", the Dark Reprise of "I Can't Imagine", Mary briefly echoes her previous "I Want" Song "Fly Into The Future". In the last reprise of "Nothing Like a Friend" from the Theatreworks version, Mary sings "I want(ed) to see if i even like my friends".
In an unusual variation, Merrily We Roll Along is told in reverse order, so the ironic echoes are heard first. For instance, Mary's rather desperate reprise of "Old Friends" is after the friendship has fallen apart; we don't hear it sung genuinely until several more timeskips back.
The Last Five Years is a show of ironic echoes. Especially the line in "See I'm Smiling" and "I Can Do Better" about "you, and you, and nothing but you. Miles and piles of you." However, there are many others.
Pippin sings several times throughout the course of the show that "Rivers belong where they can ramble/Eagles belong where they can fly/I've got to be where my spirit can run free." At the end of the show, he decides "I'm not a river/Or a giant bird that soars to the sea/And if I'm never tied to anything/I'll never be free."
In the musical version of The Addams Family, Morticia refuses to dance with Gomez after learning he's keeping something from her, telling him, "Not today." Later, Gomez is distraught that Morticia is leaving him and wondering if it's the end of his marriage and their family. He eventually proclaims, "Not today!"
In Cirque du Soleil's Amaluna, the Peacock Dance act gets the ironic echo treatment when the Black Peacocks separate Miranda and Romeo, and cast the latter into the Underworld, complete with a Dark Reprise of the Peacock Goddess's theme ("Enchanted Reunion"). Two acts later, Miranda's waterbowl is used to imprison Romeo during Cali's juggling act.
In the stage play A Few Good Men, Lt. Kaffey does this to Col. Jessep in a deconstruction of his motives.
Kaffee: You trashed the law! But hey, we understand, you're permitted. You have a greater responsibility than we can possibly fathom. You provide us with a blanket of freedom. We live in a world that has walls and those walls have to be guarded by men with guns, and nothing is going to stand in your way of doing it. Not Willie Santiago, not Dawson and Downey, not Markinson, not 1,000 armies, not the Uniform Code of Military Justice, and not the Constitution of the United States! That's the truth isn't it Colonel? I can handle it.