8 But this, as I said, I do not mention, but allow it to pass away in silence. This one thing I ask, above all, What reason is there if I kill a pig, that a god changes his state of mind, and lays aside his angry feelings and frenzy; that if I consume a pullet, a calf under his eyes and on his altars, he forgets the wrong which I did to him, and abandons completely all sense of displeasure? What passes from this act to modify his resentment? Or of what service is a goose, a goat, or a peacock, that from its blood relief is brought to the angry god?
Do the gods, then, make insulting them a matter of payment? And as little boys, to induce them to give up their fits of passion and desist from their wailings, get little sparrows, dolls, ponies, puppets, with which they may be able to divert themselves, do the immortal gods in such wise receive these gifts from you, that for them they may lay aside their resentment, and be reconciled to those who offended them? And yet I thought that the gods— if only it is right to believe that they are really moved by anger— lay aside their anger and resentment, and forgive the sins of the guilty, without any price or reward.
For this belongs specially to deities, to be generous in forgiving, and to seek no return for their gifts. But if this cannot be, it would be much wiser that they should continue obstinately offended, than that they should be softened by being corrupted with bribes. For the multitude increases of those who sin, when there is hope given of paying for their sin; and there is little hesitation to do wrong, when the favour of those who pardon offenses may be bought.
Source: Against the Heathen (New Advent)