3 When, however, the Scripture terms them [gods] which are no gods, it does not, as I have already remarked, declare them as gods in every sense, but with a certain addition and signification, by which they are shown to be no gods at all. As with David: “The gods of the heathen are idols of demons;” and, “You shall not follow other gods.” For in that he says “the gods of the heathen”— but the heathen are ignorant of the true God— and calls them “other gods,” he bars their claim [to be looked upon] as gods at all.
But as to what they are in their own person, he speaks concerning them; “for they are,” he says, “the idols of demons.” And Esaias: “Let them be confounded, all who blaspheme God, and carve useless things; even I am witness, says God.” He removes them from [the category of] gods, but he makes use of the word alone, for this [purpose], that we may know of whom he speaks. Jeremiah also says the same: “The gods that have not made the heavens and earth, let them perish from the earth which is under the heaven.” For, from the fact of his having subjoined their destruction, he shows them to be no gods at all.
Elias, too, when all Israel was assembled at Mount Carmel, wishing to turn them from idolatry, says to them, “How long do you halt between two opinions? If the Lord be God, follow Him.” And again, at the burnt-offering, he thus addresses the idolatrous priests: “You shall call upon the name of your gods, and I will call on the name of the Lord my God; and the Lord that will hearken by fire, He is God.” Now, from the fact of the prophet having said these words, he proves that these gods which were reputed so among those men, are no gods at all. He directed them to that God upon whom he believed, and who was truly God; whom invoking, he exclaimed, “Lord God of Abraham, God of Isaac, and God of Jacob, hear me today, and let all this people know that You are the God of Israel.”
Source: Adversus haereses (New Advent)