4 If perchance it is not this, are victims not slain in sacrifice to the gods, and cast upon their flaming altars to give them some pleasure and delight? And can any man persuade himself that the gods become mild as they are exhilarated by pleasures, that they long for sensual enjoyment, and, like some base creatures, are affected by agreeable sensations, and charmed and tickled for the moment by a pleasantness which soon passes away? For that which is overcome by pleasure must be harassed by its opposite, sorrow; nor can that be free from the anxiety of grief, which trembles with joy, and is elated capriciously with gladness. But the gods should be free from both passions, if we would have them to be everlasting, and freed from the weakness of mortals.
Moreover, every pleasure is, as it were, a kind of flattery of the body, and is addressed to the five well-known senses; but if the gods above feel it, they must partake also of those bodies through which there is a way to the senses, and a door by which to receive pleasures. Lastly, what pleasure is it to take delight in the slaughter of harmless creatures, to have the ears ringing often with their piteous bellowings, to see rivers of blood, the life fleeing away with the blood, and the secret parts having been laid open, not only the intestines to protrude with the excrements, but also the heart still bounding with the life left in it, and the trembling, palpitating veins in the viscera?
We half-savage men, nay rather—to say with more candour what it is truer and more candid to say—we savages, whom unhappy necessity and bad habit have trained to take these as food, are sometimes moved with pity for them; we ourselves accuse and condemn ourselves when the thing is seen and looked into thoroughly, because, neglecting the law which is binding on men, we have broken through the bonds which naturally united us at the beginning. Will any one believe that the gods, who are kind, beneficent, gentle, are delighted and filled with joy by the slaughter of cattle, if ever they fall and expire pitiably before their altars? And there is no cause, then, for pleasure in sacrifices, as we see, nor is there a reason why they should be offered, since there is no pleasure afforded by them; and if perchance there is some, it has been shown that it cannot in any way belong to the gods.
Source: Against the Heathen (New Advent)