1 John 5:21

So, when you allege that the ornaments of the heathen deities are found no less with God, with the object of claiming among these for general use the head-crown, you already lay it down for yourself, that we must not have among us, as a thing whose use we are to share with others, what is not to be found in the service of God. Well, what is so unworthy of God indeed as that which is worthy of an idol? But what is so worthy of an idol as that which is also worthy of a dead man? For it is the privilege of the dead also to be thus crowned, as they too straightway become idols, both by their dress and the service of deification, which (deification) is with us a second idolatry. Wanting, then, the sense, it will be theirs to use the thing for which the sense is wanting, just as if in full possession of the sense they wished to abuse it. …

19. To these morbid and pernicious affections of the mind divine Scripture applies a remedy, by repeating, with the impressiveness of wholesome admonition, a familiar fact, in the words, “Eyes have they, but they see not; they have ears, but they hear not,” etc. For these words, by reason of their being so plain, and commending themselves to all people as true, are the more effective in striking salutary shame into those who, when they present divine worship before such images with religious fear, and look upon their likeness to living beings while they are venerating and worshipping them, and utter petitions, offer sacrifices, and perform vows before them as if present, are so completely overcome, that they do not presume to think of them as devoid of perception. …

2. This would be a real difficulty and one for ever incapable of solution were it not solved by the witness of John himself, who immediately goes on to say,“My little children, guard yourselves from idols.” If everyone that is born of God sinneth not, and cannot be tempted by the devil, how is it that he bids them beware of temptation? Again in the same Epistle we read:“If we say that we have no sins, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. If we say that we have not sinned, we make him a liar, and his word is not in us.” I suppose that John was baptized and was writing to the baptized: I imagine too that all sin is of the devil. Now John confesses himself a sinner, and hopes for forgiveness of sins after baptism. …