This is an indication of the severity of their idolatry, which was synonymous with spiritual prostitution and adultery (Exodus 34:15–16; Deuteronomy 31:16). God had told them after the golden calf affair to guard themselves against making any covenants with the Canaanites or toleration of their gods, for the Lord is a passionate God. “God sees all sin—all idolatry—as 'adultery.' He does not merely want us to know and obey him as a citizen obeys a king, or merely to follow him as a sheep follows a shepherd. He wants us to know him and love him as a wife loves a husband. In both the Old and New Testaments, God calls himself our Bridegroom (Ezekiel 16:1–63; Ephesians 5:1–33; Revelation 19:1–21). A marriage is an exclusive, legal commitment, but it is not only that; real marriage involves deep, intimate, selfless love." In this case, then, Israel was a married prostitute.
1 This explains why God responds with intense anger towards his people (Judges 2:20). His jealousy/passion is kindled whenever his people flirt with other gods. How much more so when they turn their back on him and commit spiritual harlotry by attaching themselves to the gods of this land. [Also], the gods competing with Yahweh for the allegiance of his people are lusty young fertility gods, who seduce the Israelites with promises of prosperity and security. Furthermore, in contrast to the lofty theology and the austere morality of Yahwism, the Canaanite religious system offered exciting and often erotic cult rituals.
2
17 Yet they did not listen to their judges, for they whored after other gods and bowed down to them. They soon turned aside from the way in which their fathers had walked, who had obeyed the commandments of the LORD, and they did not do so.