O shame to men! Devil with devil damned
     Firm concord holds, men only disagree
     Of Creatures rational, though under hope
     Of heavenly Grace: and God proclaiming peace,
     Yet live in hatred, enmity, and strife
     Among themselves, and levy cruel wars,
     Wasting the earth, each other to destroy:
     As if (which might induce us to accord)
     Man had not hellish foes enough besides,
     That day and night for his destruction wait.

John Milton, Paradise Lost, Book 2, ll. 496-505