“Even the gods fight boredom in vain.”

Young Adventure (1918), The Quality of Courage
Context: p>Was it not better so to lie?
The fight was done. Even gods tire
Of fighting... My way was the wrong.
Now I should drift and drift along
To endless quiet, golden peace...
And let the tortured body cease.And then a light winked like an eye.
... And very many miles away
A girl stood at a warm, lit door,
Holding a lamp. Ray upon ray
It cloaked the snow with perfect light.
And where she was there was no night
Nor could be, ever. God is sure,
And in his hands are things secure.</p

Quoted by Plato in the dialogue Protagoras, 345d http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0177%3Atext%3DProt.%3Asection%3D345d (Simonides Fr. 37.1.27 ff.).
Variant translations:
The gods do not fight against necessity.
Not even the gods war against necessity.
I praise and love all men who do no sin willingly; but with necessity even the gods do not contend.

Sí, es necesario padecer, aún en vano, para no vivir en vano.
Voces (1943)

Jean-Christophe (1904 - 1912), Journey's End: The Burning Bush (1911)
Context: "Thou art not alone, and thou dost not belong to thyself. Thou art one of My voices, thou art one of My arms. Speak and strike for Me. But if the arm be broken, or the voice be weary, then still I hold My ground: I fight with other voices, other arms than thine. Though thou art conquered, yet art thou of the army which is never vanquished. Remember that and thou wilt fight even unto death."
"Lord, I have suffered much!"
"Thinkest thou that I do not suffer also? For ages death has hunted Me and nothingness has lain in wait for Me. It is only by victory in the fight that I can make My way. The river of life is red with My blood."
"Fighting, always fighting?"
"We must always fight. God is a fighter, even He Himself. God is a conqueror. He is a devouring lion. Nothingness hems Him in and He hurls it down. And the rhythm of the fight is the supreme harmony. Such harmony is not for thy mortal ears. It is enough for thee to know that it exists. Do thy duty in peace and leave the rest to the Gods."

Tel est le malheur de notre siècle, les plus étranges égarements même ne guérissent pas de l'ennui.
Vol. II, ch. XVII
Le Rouge et le Noir (The Red and the Black) (1830)

In principio, dunque, era la noia, volgarmente chiamata caos. Iddio, annoiandosi della noia, creò la terra, il cielo, l'acqua, gli animali, le piante, Adamo ed Èva; i quali ultimi, annoiandosi a loro volta in paradiso, mangiarono il frutto proibito. Iddio si annoiò di loro e li cacciò dall'Eden.
La noia (Milano: Bompiani, 1960) pp. 10-11; Angus Davidson (trans.) Boredom (New York: New York Review of Books, 1999) p. 8.

Die Jungfrau von Orleans (The Maid of Orleans) (1801), Act III, sc. vi (as translated by Anna Swanwick)
Variants of the most commonly quoted portion:
Against stupidity the gods themselves contend in vain.
Against stupidity the gods themselves labor in vain.
Against stupidity the gods themselves fight unvictorious
Against stupidity even the gods contend in vain.
Against stupidity gods themselves contend in vain.
With stupidity the gods themselves contend in vain.
With stupidity the gods themselves struggle in vain.
Context: Folly, thou conquerest, and I must yield!
Against stupidity the very gods
Themselves contend in vain. Exalted reason,
Resplendent daughter of the head divine,
Wise foundress of the system of the world,
Guide of the stars, who art thou then if thou,
Bound to the tail of folly's uncurbed steed,
Must, vainly shrieking with the drunken crowd,
Eyes open, plunge down headlong in the abyss.
Accursed, who striveth after noble ends,
And with deliberate wisdom forms his plans!
To the fool-king belongs the world.