Augustine of Hippo, On Nature and Grace Chapter 30: Sin is Removed by Sin

Chapter 30 [XXVII.]—Sin is Removed by Sin.

He no doubt shows some acuteness in handling, and turning over and exposing, as he likes, and refuting a certain statement, which is made to this effect, that “it was really necessary to man, in order to take from him all occasion for pride and boasting, that he should be unable to exist without sin.” He supposes it to be “the height of absurdity and folly, that there should have been sin in order that sin might not be; inasmuch as pride is itself, of course, a sin.” As if a sore were not attended with pain, and an operation did not produce pain, that pain might be taken away by pain. If we had not experienced any such treatment, but were only to hear about it in some parts of the world where these things had never happened, we might perhaps use this man’s words, and say, It is the height of absurdity that pain should have been necessary in order that a sore should have no pain.