Manasseh during his minority naturally fell under the influence of the chief Jewish nobles, with whom the pure religion of Yahweh was always unpopular (compare 2 Chronicles 24:17-18; Jeremiah 8:1-2). They seem to have persuaded him, not only to undo Hezekiah's work, but to proceed to lengths in polytheism, magic, and idolatry, unknown before. The sins of Manasseh's reign appear to have been those which filled up the measure of Judah's iniquity, and brought down the final sentence of doom on the last remnant of the chosen people (2 Kings 23:26; compare Jeremiah 15:4).

After the abominations of the heathen - He exactly copied the conduct of those nations which God had cast out of that land.

And he did that which was evil in the sight of the Lord,.... Was guilty of idolatry:

after the abomination of the Heathen, whom the Lord cast out before the children of Israel: the old Canaanites; he committed idolatry in imitation of them, and as the Phoenicians now did before the children of Israel: the old Canaanites; he committed idolatry in imitation of them, and as the Phoenicians now did.

Having begun to reign at this early age, he did not choose his father's ways, but set up the idolatry of his father Ahab again, since the godless party in the nation, at whose head chiefs, priests, and (false) prophets stood, and who would not hearken to the law of the Lord, and in the time of Hezekiah had sought help against Assyria not from Jehovah, but from the Egyptians (Isaiah 28:7, Isaiah 28:14., Isaiah 30:9.), had obtained control of the young an inexperienced king, and had persuaded him to introduce idolatry again. On 2 Kings 21:2 cf. 2 Kings 8:18 and 2 Kings 16:3.

And he did that which was evil in the sight of the LORD, after the abominations of the heathen, whom the LORD cast out before the children of Israel.

21:1-9 Young persons generally desire to become their own masters, and to have early possession of riches and power. But this, for the most part, ruins their future comfort, and causes mischief to others. It is much happier when young persons are sheltered under the care of parents or guardians, till age gives experience and discretion. Though such young persons are less indulged, they will afterwards be thankful. Manasseh wrought much wickedness in the sight of the Lord, as if on purpose to provoke him to anger; he did more evil than the nations whom the Lord destroyed. Manasseh went on from bad to worse, till carried captive to Babylon. The people were ready to comply with his wishes, to obtain his favour and because it suited their depraved inclinations. In the reformation of large bodies, numbers are mere time-servers, and in temptation fall away.