Concerning the Nature of Good, Against the Manichaeans

But pain which some suppose to be in a special manner an evil, whether it be in mind or in body, cannot exist except in good natures. For the very fact of resistance in any being leading to pain, involves a refusal not to be what it was, because it was something good; but when a being is compelled to something better, the pain is useful, when to something worse, it is useless. Therefore in the case of the mind, the will resisting a greater power causes pain; in the case of the body, sensation resisting a more powerful body causes pain.

But evils without pain are worse: for it is worse to rejoice iniquity than to bewail corruption; yet even such rejoicing cannot exist save from the attainment of inferior good things. But iniquity is the desertion of better things. Likewise in a body, a wound with pain is better than painless putrescence, which is especially called the corruption which the dead flesh of the Lord did not see, that is, did not suffer, as was predicted in prophecy: "You shall not suffer Your Holy one to see corruption." For who denies that He was wounded by the piercing of the nails, and that He was stabbed with the lance? But even what is properly called by men corporeal corruption, that is, putrescence itself, if as yet there is anything left to consume, increases by the diminution of the good.

But if corruption shall have absolutely consumed it, so that there is no good, no nature will remain, for there will be nothing that corruption may corrupt; and so there will not even be putrescence, for there will be nowhere at all for it to be.