He who sins is of the devil, for the devil has been sinning from the beginning. To this end the Son of God was revealed, that he might destroy the works of the devil.
For the Devil sinneth from the beginning As before he spoke not of Christ personally, when he said that he is righteous, but mentioned him as the fountain and the cause of righteousness; so now, when he says that the Devil sins, he includes his whole body, even all the reprobate; as though he had said, this belongs to the Devil, to entice men to sin. It hence follows, that his members, and all who are ruled by him, give themselves up to commit sin. But the beginning which the Apostle mentions, is not from eternity, as when he says that the Word is from the beginning, for there is a wide difference between God and creatures. Beginning as to God, refers to no time. Since, then, the Word was always with God, you can find no point of time in which he began to be, but you must necessarily admit his eternity. But here John meant no other thing than that the Devil had been an apostate since the creation of the world, and that from that time he had never ceased to scatter his poison among men. 