Albert Barnes Commentary 2 Kings 17:7

"And it was so, because the children of Israel had sinned against Jehovah their God, who brought them up out of the land of Egypt from under the hand of Pharaoh king of Egypt, and had feared other gods," — 2 Kings 17:7 (ASV)

The reasons God suffered the Israelites to be deprived of their land and carried into captivity were:

1. Their idolatries;
2. Their rejection of the Law;
3. Their disregard of the warning voices of prophets and seers.