For millenniums morality meant obedience to custom, respect for inherited usage. The free, exceptional man was immoral, because he broke with the tradition which the others regarded with superstitious fear. Very commonly he took the same view and was himself seized by the terror he inspired. Thus a popular morality of custom was unconsciously elaborated by all who belonged to the tribe; since fresh examples and proofs could always be found of the alleged relation between guilt and punishment--if you behave in such and such a way, it will go badly with you. Now, as it generally does go badly, the allegation was constantly confirmed; and thus popular morality, a pseudoscience on a level with popular medicine, continually gained ground.
Manners and customs represented the experiences of bygone generations concerning what was supposed to be useful or harmful; the sense of morality, however, does not attach to these experiences as such, but only to their age, their venerability and consequent incontestability. In the state of war in which a tribe existed in old times, threatened on every side, there was no greater gratification, under the sway of the strictest morality of custom, than cruelty. Cruelty is one of the oldest festal and triumphal joys of mankind. It was thought that the gods, too, might be gratified and festively disposed by offering them the sight of cruelties--and thus the idea insinuated itself into the world that voluntary self-torture, mortification and abstinence are also of great value, not as discipline, but as a sweet savour unto the Lord.
Christianity as a religion of the past unceasingly practised and preached the torture of souls. Imagine the state of the mediæval Christian, when he supposed he could no longer escape eternal torment. Eros and Aphrodite were in his imagination powers of hell, and death was a terror.