Nicene and Post-Nicene Fathers, Vol. V:
A Treatise Against Two Letters of the...: Chapter 27

Chapter 27.—In What Sense Lust is Called Sin in the Regenerate.

But concerning that concupiscence of the flesh of which they speak, I believe that they are deceived, or that they deceive; for with this even he that is baptized must struggle with a pious mind, however carefully he presses forward, and is led by the Spirit of God. But although this is called sin, it is certainly so called not because it is sin, but because it is made by sin, as a writing is said to be some one’s “hand” because the hand has written it. But they are sins which are unlawfully done, spoken, thought, according to the lust of the flesh, or to ignorance—things which, once done, keep their doers guilty if they are not forgiven. And this very concupiscence of the flesh is in such wise put away in baptism, that although it is inherited by all that are born, it in no respect hurts those that are born anew. And yet from these, if they carnally beget children, it is again derived; and again it will be hurtful to those that are born, unless by the same form it is remitted to them as born again, and remains in them in no way hindering the future life, because its guilt, derived by generation, has been put away by regeneration; and thus it is now no more sin, but is called so, whether because it became what it is by sin, or because it is stirred by the delight of sinning, although by the conquest of the delight of righteousness consent is not given to it. Nor is it on account of this, the guilt of which has already been taken away in the laver of regeneration, p. 386 that the baptized say in their prayer, “Forgive us our debts, as we also forgive our debtors;” 2590 but on account of sins which are committed, whether in consentings to it, when what is right is overcome by that which pleases, or when by ignorance evil is accepted as if it were good. And they are committed, whether by acting, or by speaking, or—and this is the easiest and the quickest—by thinking. From all which things what believer ever will boast that he has his heart pure? or who will boast that he is pure from sin? 2591 Certainly that which follows in the prayer is said on account of concupiscence: “Lead us not into temptation, but deliver us from evil.” “For every one,” as it is written, “is tempted when he is drawn away of his own concupiscence, and enticed; then, when concupiscence hath conceived, it bringeth forth sin.” 2592

Footnotes

Matt. vi. 12.

Prov. xx. 9.

Jas. i. 14.