"Dreams save us. Dreams lift us up and transform us. And on my soul, I swear — until my dream of a world where dignity, honor and justice becomes the reality we all share — I'll never stop fighting. Ever."
The iconic "I fight for Truth, Justice and The American Way."
The Pledge of a Superman, from World's Finest Comics #213:
I will use this power for all the good that can be done... To work for peace... To encourage virtue... And above all, to preserve life, in all its forms... Or failing in that, to give up this power...forever!
Krypto the Superdog was part of the Space Canine Patrol Agency, whose slogan is as follows: "Big Dog! Big Dog! Bow wow wow! We'll crush evil... Now, now, now!" If "big dog, big dog, bow wow wow" sounds anticlimactic, it's because it's a Shout-Out to the Yale chorus ("Bulldog, bulldog, bow wow wow...")
Barry declares what it means to be The Flash as he runs himself to death saving the entire multiverse in JLA Incarnations #5:
"Light calling to me...drawing me forward...what is it? I hear it in my heart.
The essence of what I am. The source and the end. Speed itself.
It reminds me. What I stand for. What the League stands for.
My life doesn’t matter. I can save them. If I just let go...
and then I am in it and I am a part of it and I am everywhere.
I am the lightning and I am reaching out.
And there are no accidents!''
The Golden Age Sandman, as revived in the 1990's Sandman Mystery Theatre series: "None can escape the Sandman's dark dream."
He also used to leave a poem on his defeated opponents: "There is no land beyond the law / Where tyrants rule with unshakable power! / 'Tis but a dream from which the evil wake / To face their fate, their terrifying hour!"
In "The Oath", Doctor Strange manages to make the Hippocratic Oath badass:
"I have sworn many oaths in my day, to every being from Hoggoth to Watoomb. But the first oath I swore was the Hippocratic. 'I will prescribe regimens for the good of my patients, according to my judgement and ability, and I will do so at any cost.' "
John Custer: Don't take no shit off fools. Judge a person by what's in 'em, not how they look. An' you do the right thing. Be one of the good guys. 'Cause there's way too many of the bad.
Frank Drake of the Nightstalkers distills the entirety of Silver Age Superhero philosophy into four words. Do good. Fight evil.
In the Sonic the Hedgehog series, but most commonly the Archie comics, theres always a badass creed used to summon upon the power of one of the emeralds, usually the Master Emerald, for a specific request, usually along the lines of "The servers are the seven chaos emerald, chaos is power, enriched by the heart" followed by the request. The badass-ness of this is shown in its full height at the end of the Enerjak arc, as Knuckles and Doctor Finitevus both channel the energy of the Master Emerald and prepare to strike the other down with one energy charged punch, in a way that seems to invoke the feeling of a battle between Hal Jordan and Sinestro.
Knuckles: The servers are the seven chaos...
Finitevus: The servants are the seven chaos...
Knuckles: Chaos is power, enriched by the heart...
Finitevus: Chaos is power, controlled by my will..
Knuckles: The controller exists to unify the chaos!
Finitevus: The controller exists to enslave the chaos!
In The Metabarons, Bushitaka, the Castaka family code. It allows victory, or death in pursuit of victory as the only possible choices for a warrior. At any cost.
The Oath of the Skull from The Phantom is an iconic classic in the genre.
"I swear to devote my life to the destruction of piracy, greed, cruelty, and injustice, in all their forms, and my sons and their sons shall follow me."