Clement of Alexandria

Now it is adultery, if one, abandoning the ecclesiastical and true knowledge, and the persuasion respecting God, accedes to false and incongruous opinion, either by deifying any created object, or by making an idol of anything that exists not, so as to overstep, or rather step from, knowledge. And to the Gnostic false opinion is foreign, as the true belongs to him, and is allied with him. Wherefore the noble apostle calls one of the kinds of fornication, idolatry, in following the prophet, who says: "[My people] hath committed fornication with stock and stone. They have said to the stock, Thou art my father; and to the stone, Thou hast begotten me."