Does religious conviction provide a powerful reason for killing? Undeniably it often does. It also often provides the sole compelling reason for refusing to kill, or for being merciful, or for seeking peace; only the profoundest ignorance of history could prevent one from recognizing this. For the truth is that religion and irreligion are cultural variables, but killing is a human constant.

Atheist Delusions: The Christian Revolution and Its Fashionable Enemies