Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
4 Kings (2 Kings) Chapter 21
When Hezekiah died at the age of fifty-four, his son was but twelve years old. Beguiled himself, Manasseh seduced the people, who were but too willing to commit greater iniquity than the nations who knew not God. The particular events of Manasseh's life are not related here. The Holy Ghost, having given us the details, in that which precedes, of God's public government in Israel, until He had said, "Lo-ruhamah," then shews us God's dealings with Judah, governed by the conduct of their kings, until God has said, "Lo-ammi." This had been already announced on account of Manasseh's heinous sins; and Josiah's piety could not change the just judgment of God. There was yet for Judah some prolongation of tranquillity; but their repentance under Josiah was but outward [See Note #1], and evil regained the mastery immediately after his death. Amon did but follow the evil ways of his father Manasseh.
Note #1
See Jer 3:10. This passage teaches us how seldom the heart, which is what God judges, corresponds with the semblance of zeal for Him and for His glory, which appears on the surface, when, moved by the Spirit of God, a man of faith presents himself to promote His glory. See also under Hezekiah's reign the condition of the people and God's judgment-Isaiah 22.