Jeremiah 9:14

But have walked after the imagination of their own heart, and after Baalim, which their fathers taught them:

But have walked after the imagination of their own heart,.... What their own hearts devised, chose, and were best pleased with;

See Gill on "Jeremiah 7:24",

and after Baalim; the idols of the Gentiles; these they served and worshipped, and not the true God:

which their fathers taught them; which was so far from excusing them, that it was an aggravation of their sin, that they had continued in their wicked ways and idolatrous practices, from age to age, from one generation to another. This then was the cause of their calamity and destruction; they had forsaken the law of the Lord, and had broken that; they had chose their own ways, and had been guilty of idolatrous practices time out of mind; wherefore the Lord had shown much longsuffering and patience with them, and would now no longer forbear he was just and righteous in his doings.