Charles Ellicott Commentary 2 Kings 21:2

"And he did that which was evil in the sight of Jehovah, after the abominations of the nations whom Jehovah cast out before the children of Israel." — 2 Kings 21:2 (ASV)

And he did that which was evil. — Perhaps under the pernicious influence of his courtiers. (Compare the case of Rehoboam.)

After the abominations. — Compare Deuteronomy 29:17; 1 Kings 11:5.

The heathen ... cast.— The nations ... dispossessed — i.e., the peoples of Canaan (2 Kings 17:8).