Chapter 22. The Law of God, conscience and sin. (Book 4. Life in Christ, sacraments, worship, conscience, future resurrection) (On the Orthodox Faith) (Damascene, John)

The Deity is good and more than good, and so is his will. For that which God wishes is good. Moreover the precept, which teaches this, is law, that we, holding by it, may walk in light: and the transgression of this precept is sin, and this continues to exist on account of the assault of the devil and our unconstrained and voluntary reception of it. And this, too, is called law.

So the Law of God, settling in our mind, draws it towards itself and pricks our conscience. And our conscience, too, is called a law of our mind. Further, the assault of the wicked one, that is the Law of sin, settling in the members of our flesh, makes its assault upon us through it. For by once voluntarily transgressing the Law of God and receiving the assault of the wicked one, we gave entrance to it, being sold by ourselves to sin. Therefore our body is readily impelled to it. And so the savour and perception of sin that is stored up in our body, that is to say, lust and pleasure of the body, is law in the members of our flesh.

Therefore the Law of my mind, that is, the conscience, sympathizes with the Law of God, that is, the precept, and makes that its will. But the Law of sin, that is to say, the assault made through the Law that is in our members, or through the lust and inclination and movement of the body and of the irrational part of the soul, is in opposition to the Law of my mind, that is to conscience, and takes me captive (even though I make the Law of God my will and set my love on it, and make not sin my will), by reason of commixture: and through the softness of pleasure and the lust of the body and of the irrational part of the soul, as I said, it leads me astray and induces me to become the servant of sin.

But what the Law could not do, in that it was weak through the flesh, God, sending his own Son in the likeness of sinful flesh (for he assumed flesh but not sin) condemned sin in the flesh, that the righteousness of the Law might be fulfilled in us who walk not after the flesh but in the Spirit. For the Spirit helps our infirmities and affords power to the Law of our mind, against the Law that is in our members. For the verse, we do not know what we should pray for as we ought, but the Spirit itself makes intercession with groanings that cannot be uttered, itself teaches us what to pray for. So it is impossible to carry out the precepts of the Lord except by patience and prayer.