Psalms 106:39

Thus were they defiled with their own works - By their very attempts to deliver themselves from sin. They were corrupt, and the consciousness that they were sinners led them to the commission of even greater enormities in attempting to expiate their guilt, even by the sacrifice of their own sons and daughters. Thus all the religions of the pagan begin in sin, and end in sin. The consciousness of sin only leads to the commission of greater sin; to all the abominations of idol-worship; to the sacrifice - the murder - of the innocent, with the vain hope of thus making expiation for their crimes. Sinners have never yet been able to devise a way by which they may make themselves pure. It is only the great Sacrifice made on the cross which meets the case; which provides expiation; and which saves from future sin.

And went a whoring - Apostacy from God and backsliding are ofen illustrated in the Scriptures by the violation of the marriage compact, as the relation between God and his people is often compared with the relation between a husband and wife. Compare Isaiah 62:5; Jeremiah 3:14; Jeremiah 7:9; Jeremiah 13:27; Ezekiel 16:20, Ezekiel 16:22, Ezekiel 16:25, Ezekiel 16:33; Ezekiel 23:17.

With their own inventions - More literally, With their own works. See the notes at Psalms 106:29.