Why does the Lord say they have forsaken his law and stubbornly followed their own hearts and gone after Baals?

Jeremiah, the true prophet, gives the definitive answer to the question because he speaks on behalf of the Lord. And the Lord says, Because they have forsaken my law that I set before them and have not obeyed my word or walked in accord with it, but have stubbornly followed their own hearts and have gone after the Baals as their fathers taught them. The background to these words is the Lord’s covenant with Israel. At Mt Sinai the Lord established his covenant with them and they committed themselves to obeying his word (Exodus 19:4–8). When Moses renews this covenant with the next generation of Israelites on the border of the land, just before they are about to enter, he reminds them of their commitment to obey the Lord and not turn to other gods (Deuteronomy 4:1–5:33). But Israel failed in her covenant commitments, none more so than the remaining generation living in Judah during Jeremiah’s time. The reason judgment is coming to them can be summed up in one word: serirut, usually translated as stubbornness. Other than Deuteronomy 29:18 and Psalm 81:13, this word is found only in Jeremiah (see Jeremiah 3:17; Jeremiah 7:24; Jeremiah 9:13; Jeremiah 11:8; Jeremiah 13:10; Jeremiah 16:12; Jeremiah 18:12; Jeremiah 23:17). It involves a defiant attitude toward the Lord.¹ The people have forsaken the Lord’s law and not lived in obedience to his word but have rather stubbornly followed their own hearts. This stubborn disobedience has taken them away from the Lord and they have gone after the Baals as the object of their worship. In every way the people of Judah have broken their covenant commitments and that is why the Lord’s judgment is coming. Any other explanations of the present and the future in Judah are simply foolishness.