2 Kings 17:33

They feared the LORD, and served their own gods, after the manner of the nations whom they carried away from thence.

The verse describes the people resettled in Samaria who dwelt close by the returned Israelites, a mixed race sprung up through intermarriage of heathen colonists from the provinces of Assyria with the remnant of the ten tribes left in Samaria and Galilee. Their ancestors had belonged to Israel, but because of transgression in neglecting to obey the statutes of God the Lord suffered an idolatrous nation to overcome them. Through intermingling with idolaters for many generations their religion was gradually contaminated.

To fear the LORD while serving their own gods was a mixture of Judaism and heathenism, preserving reverence for the true God while also worshiping idols after the manner of the nations from which they had come and among whom they lived. They treated images of wood and stone as mere reminders of the living God, the Ruler of the universe, before which they bowed in worship. Yet in heart and practice they were idolaters, prone to be led to revere their graven images.

After they sought teachers from the Jews and made efforts to reform, their views of God and His requirements became clearer. Their service then followed the ceremonies given through Moses and resembled that of the Jews, keeping worship according to the Mosaic ritual. To strengthen alliance the Samaritans promised to adopt the Jewish faith and customs more fully. Yet they mingled that worship with the taint of idolatry and never wholly renounced it, to a certain degree still clinging to it and not entirely abandoning it.

That mixed character continued after the exile, when Jews expelled from the congregation for refusing to separate from idolaters joined the Samaritans. Others who chose exile with idolatrous spouses also joined them, including some who had held high positions in the work of God and afterward cast in their lot fully with them. That divided loyalty kept a lack of harmony with the Jews.

When refused a share in rebuilding the temple at Jerusalem the apostates built a rival temple on Mount Gerizim in opposition to the house of God at Jerusalem. They clung to their own traditions and forms of worship, refusing to respect Jerusalem as the true place of worship. They would not acknowledge the temple at Jerusalem as the house of God nor admit that the religion of the Jews was superior to their own. Their continued claim to be the people of God became the source of schism, emulation, and enmity between the two nations from generation to generation.