Yea, they sacrificed their {u} sons and their daughters unto devils,

(u) He shows how monstrous a thing idolatry is, which can win us to things abhorring to nature, while God's word cannot obtain small things.

Wesley's Notes

106:37 Devils - They did not worship God as they pretended, but devils in their idols; for those spirits, which were supposed by the Heathen idolaters to inhabit in their images, were not good spirits, but evil spirits, or devils.

Jamieson-Fausset-Brown Bible Commentary

37. unto devils-Septuagint, "demons" (compare 1Co 10:20), or "evil spirits."

Matthew Henry's Concise Commentary

106:34-48 The conduct of the Israelites in Canaan, and God's dealings with them, show that the way of sin is down-hill; omissions make way for commissions: when they neglected to destroy the heathen, they learned their works. One sin led to many more, and brought the judgments of God on them. Their sin was, in part, their own punishment. Sinners often see themselves ruined by those who led them into evil. Satan, who is a tempter, will be a tormentor. At length, God showed pity to his people for his covenant's sake. The unchangeableness of God's merciful nature and love to his people, makes him change the course of justice into mercy; and no other change is meant by God's repentance. Our case is awful when the outward church is considered. When nations professing Christianity, are so guilty as we are, no wonder if the Lord brings them low for their sins. Unless there is general and deep repentance, there can be no prospect but of increasing calamities. The psalm concludes with prayer for completing the deliverance of God's people, and praise for the beginning and progress of it. May all the people of the earth, ere long, add their Amen.