Serenus: No one who has experienced the conflicts of the inner man, can doubt that our foes are continually lying in wait for us. But we mean that they oppose our progress in such a way that we can think of them as only inciting to evil things and not forcing. But no one could altogether avoid whatever sin they were inclined to imprint upon our hearts, if a strong impulse was present to force (evil) upon us, just as it is to suggest it. Wherefore as there is in them ample power of inciting, so in us there is a supply of power of rejection, and of liberty of acquiescing. But if we are afraid of their power and assaults, we may also claim the protection and assistance of God against them, of which we read: “For greater is He who is in us than he who is in this world:” and His aid fights on our side with much greater power than their hosts fight against us; for God is not only the suggester of what is good, but the maintainer and insister of it, so that sometimes He draws us towards salvation even against our will and without our knowing it. It follows then that no one can be deceived by the devil but one who has chosen to yield to him the consent of his own will: as Ecclesiastes clearly puts it in these words: “For since there is no gainsaying by those who do evil speedily, therefore the heart of the children of men is filled within them to do evil.” It is therefore clear that each man goes wrong from this; viz., that when evil thoughts assault him he does not immediately meet them with refusal and contradiction, for it says: “resist him, and he will flee from you.”
Reproduced in full. Translation: Nicene and Post-Nicene Fathers, series 2, vol. 11 (Schaff and Wace, 1894), public domain (Public domain).