Genesis 5:3

3.And begat a son in his own likeness. We have lately said that Moses traces the offspring of Adam only through the line of Seth, to propose for our consideration the succession of the Church. In saying that Seth begat a son after his own image, he refers in part to the first origin of our nature: at the same time its corruption and pollution is to be noticed, which having been contracted by Adam through the fall, has flowed down to all his posterity. If he had remained upright, he would have transmitted to all his children what he had received: but now we read that Seth, as well as the rest, was defiled; because Adams who had fallen from his original state, could beget none but such as were like himself. If any one should object that Seth with his family had been elected by the special grace of God: the answer is easy and obvious; namely, that a supernatural remedy does not prevent carnal generation from participating in the corruption of sin. Therefore, according to the flesh, Seth was born a sinner; but afterwards he was renewed by the grace of the Spirit. This sad instance of the holy patriarch furnishes us with ample occasion to deplore our own wretchedness.