The house of Israel was the first to be carried away into captivity. This began in 721 BC at the hand of the Assyrians. Dispersion was a curse because they “served idols” and “abandoned all the commandments of the Lord their God“.

“In the ninth year of Hoshea, the king of Assyria captured Samaria, and he carried the Israelites away to Assyria and placed them in Halah, and on the Habor, the river of Gozan, and in the cities of the Medes. And this occurred because the people of Israel had sinned against the Lord their God, who had brought them up out of the land of Egypt from under the hand of Pharaoh king of Egypt, and had feared other gods and walked in the customs of the nations whom the Lord drove out before the people of Israel, and in the customs that the kings of Israel had practiced. And the people of Israel did secretly against the Lord their God things that were not right. They built for themselves high places in all their towns, from watchtower to fortified city. They set up for themselves pillars and Asherim on every high hill and under every green tree, and there they made offerings on all the high places, as the nations did whom the Lord carried away before them. And they did wicked things, provoking the Lord to anger, and they served idols, of which the Lord had said to them, “You shall not do this.” Yet the Lord warned Israel and Judah by every prophet and every seer, saying, “Turn from your evil ways and keep my commandments and my statutes, in accordance with all the Law that I commanded your fathers, and that I sent to you by my servants the prophets.”

But they would not listen, but were stubborn, as their fathers had been, who did not believe in the Lord their God. They despised his statutes and his covenant that he made with their fathers and the warnings that he gave them. They went after false idols and became false, and they followed the nations that were around them, concerning whom the Lord had commanded them that they should not do like them. And they abandoned all the commandments of the Lord their God, and made for themselves metal images of two calves; and they made an Asherah and worshiped all the host of heaven and served Baal. And they burned their sons and their daughters as offerings and used divination and omens and sold themselves to do evil in the sight of the Lord, provoking him to anger. Therefore the Lord was very angry with Israel and removed them out of his sight. None was left but the tribe of Judah only. 

Judah also did not keep the commandments of the Lord their God, but walked in the customs that Israel had introduced. And the Lord rejected all the descendants of Israel and afflicted them and gave them into the hand of plunderers, until he had cast them out of his sight. When he had torn Israel from the house of David, they made Jeroboam the son of Nebat king. And Jeroboam drove Israel from following the Lord and made them commit great sin. The people of Israel walked in all the sins that Jeroboam did. They did not depart from them, until the Lord removed Israel out of his sight, as he had spoken by all his servants the prophets. So Israel was exiled from their own land to Assyria until this day.” (2 Kings 17:6-23)

In time, the king of Assyria brought foreigners into the land of Samaria. And later, he sent one of the priests back to teach them the ways of God. But they mixed fear of God with serving false Gods.

“So one of the priests whom they had carried away from Samaria came and lived in Bethel and taught them how they should fear the Lord. But every nation still made gods of its own and put them in the shrines of the high places that the Samaritans had made, every nation in the cities in which they lived. The men of Babylon made Succoth-benoth, the men of Cuth made Nergal, the men of Hamath made Ashima, and the Avvites made Nibhaz and Tartak; and the Sepharvites burned their children in the fire to Adrammelech and Anammelech, the gods of Sepharvaim. They also feared the Lord and appointed from among themselves all sorts of people as priests of the high places, who sacrificed for them in the shrines of the high places. So they feared the Lord but also served their own gods, after the manner of the nations from among whom they had been carried away.” To this day they do according to the former manner. They do not fear the Lord, and they do not follow the statutes or the rules or the law or the commandment that the Lord commanded the children of Jacob, whom he named Israel.” (2 Kings 17:28-34)

The house of Israel did exactly what God foretold in Deuteronomy before they crossed into the land.

“The Lord will bring you and your king whom you set over you to a nation that neither you nor your fathers have known. And there you shall serve other gods of wood and stone.” (Deuteronomy 28:36)

They had broken their forefathers agreement to obey God’s law. They had violated the covenants with idol worship and God viewed that as adultery against him.