Nicene and Post-Nicene Fathers: Series I/Volume V/Concerning Man's Perfection in Righteousness/Chapter 14
(13.) The Thirteenth Breviate.
XIII. “The next question we have to ask,” says he, “is this: If man cannot be without sin, whose fault is it,—man’s own, or some one’s else? If man’s own, in what way is it his fault if he is not that which he is unable to be?” We reply, that it is man’s fault that he is not without sin on this account, because it has by man’s sole will come to pass that he has come into such a necessity as cannot be overcome by man’s sole will.