1 Cor. 10:20 - But the things which the heathens sacrifice, they sacrifice to devils, and not to God. And I would not that you should be made partakers with devils.
Deut. 32:17 - They sacrificed to devils and not to God: to gods whom they knew not: that were newly come up, whom their fathers worshiped not.
Ps 95:5 - For all the gods of the Gentiles are devils: but the Lord made the heavens.
Jer. 10:20-21 - My tabernacle is laid waste, all my cords are broken: my children are gone out from me, and they are not: there is none to stretch forth my tent any more, and to set up my curtains.
Because the pastors have done foolishly, and have not sought the Lord: therefore have they not understood, and all their flock is scattered.
Exod. 34:15-17 - Make no covenant with the men of those countries lest, when they have committed fornication with their gods, and have adored their idols, some one call thee to eat of the things sacrificed.
Neither shalt thou take of their daughters a wife for thy son, lest after they themselves have committed fornication, they make thy sons also to commit fornication with their gods.
Thou shalt not make to thyself any molten gods.
Wisd. 13:10 - But unhappy are they, and their hope is among the dead, who have called gods the works of the hands of men, gold and silver, the inventions of art, and the resemblances of beasts, or an unprofitable stone the work of an ancient hand.
St. Thomas Aquinas:
"The cause of idolatry is twofold: dispositive on the part of man; consummative on the part of the demons.
"Men were led to idolatry first by disordered affections, inasmuch as they bestowed divine honours upon someone whom they loved or venerated beyond measure. This cause is indicated in Wisdom 14:15: 'For a father being afflicted by bitter grief, made to himself the image of his son who was quickly taken away; and him who then had died as a man, he began now to worship as a god . . . ', and 14:21: 'Men serving either their affection or their king, gave the incommunicable name to stones and wood'.
"Second: By their natural love for artistic representations: uncultured men, seeing statues cunningly reproducing the figure of man, worshipped them as gods. Hence we read in Wisdom 13:11 sq., 'An artist, a carpenter has cut down a tree proper for his use in the wood . . . . . . and by the skill of his art fashioneth it and maketh it like the image of a man . . . . . and then maketh prayers to it, inquiring concerning his substance and his children or his marriage'.
"Third: By their ignorance of the true God: man, not considering the excellence of God, attributed divine worship to certain creatures excelling in beauty or virtue: Wisdom 13:1-2:' . . . . . neither by attending to the works have [men] acknowledged who was the workman, but have imagined either the fire, or the wind, or the swift air, or the circle of the stars, or the great water, or the sun and moon, to be the gods that rule the world'.
"The consummative cause of idolatry was the influence of the demons who offered themselves to the worship of erring men, giving answers from idols or doing things which to men seemed marvelous, whence the Psalmist says (Psalm 95:5): 'All the gods of the gentiles are devils'" (Summa II-II, Q. xciv, a. 4)