2 Kings 17:39

But the LORD your God ye shall fear; and he shall deliver you out of the hand of all your enemies.

The verse commands fearing and worshiping the Lord alone as God, keeping His covenant and commandments, and trusting His promise to deliver from the hand of all enemies. Israel failed to obey, fearing the Lord while also serving graven images, and this neglect of God's statutes divided its hearers from Israel. Because of that disobedience the Lord let them be overcome by an idolatrous nation, and the people brought into Samaria after Israel's conquest were intermingled with idolaters whose religion gradually contaminated their own.

They preserved reverence for the true and living God and claimed to worship Him and to be His people, yet remained idolaters who represented Him by images of wood and stone treated as reminders of the living God, bowed before them, and followed the ceremonies and forms given through Moses mingled with heathenism and the taint of idolatry without wholly giving it up. After being refused a part with the Jews in rebuilding the temple at Jerusalem, they built a rival temple on Mount Gerizim, and would not respect the temple at Jerusalem nor admit it was the true place of worship.

Later disasters and the destruction of their temple seemed a curse that forced them to believe God was punishing their apostasy, so they determined to reform and sought teachers from the Jews whose instruction made their views of God and His requirements clearer until their service nearly resembled that of the Jews, yet to a degree they still clung to idolatry. This divided worship was passed on to later generations, and the Samaritans' mixed religion of combined Judaism with heathenism and their claim led to lasting division, rivalry, and hostility between the two nations.