He walked in all the way in which his father walked and served the idols that his father served and worshiped them.
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 he walked in all the ways that his father walked in,.... In his wicked way, his idolatry, witchcraft, and murders: and served the idols that his father served, and worshipped them; Baal, Ashtoreth, and all the host of heaven, and all the carved images his father made, which it seems he only removed, but did not break in pieces, Ch2 33:22.
2Ki 21:19-22 Reign of Amon (cf. 2Ch 33:21-25). - Amon reigned only two years, and that in the spirit of his father, that is to say, worshipping all his idols. The city of Jotbah, from which his mother sprang, was, according to Jerome (in the Onom. s. v. Jethaba), urbs antiqua Judaeae; but it is not further known.
Commenting on 2 Kings 21:19-22