Amon was twenty-two years old when he became king, and he reigned in Jerusalem two years. His mother’s name was Meshullemeth daughter of Haruz; she was from Jotbah.
Here is a short account of the short and inglorious reign of Amon, the son of Manasseh. Whether Manasseh, in his blind and brutish zeal for his idols, had sacrificed his other sons - or whether, having been dedicated to his idols, they were refused by the people - so it was that his successor was a son not born till he was forty-five years old.
Commenting on 2 Kings 21:19-26
And Amon was twenty two years old when he began to reign,.... Being born in the forty fifth of his father's life, and in the thirty third of his reign: and he reigned two years in Jerusalem; which, as Abarbinel observes, was the usual time the sons of wicked kings reigned, and instances in the son of Jeroboam, Baasha, and Ahab, Kg1 15:25.
AMON'S WICKED REIGN. (Kg2 21:19-26) Amon was twenty and two years old when he began to reign--This prince continued the idolatrous policy of his father; and, after an inglorious reign of two years, he was massacred by some of his own domestics. The people slew the regicide conspirators and placed his son Josiah on the throne. Next: 2 Kings Chapter 22