Charles Ellicott Commentary 2 Kings 21:7

"And he set the graven image of Asherah, that he had made, in the house of which Jehovah said to David and to Solomon his son, In this house, and in Jerusalem, which I have chosen out of all the tribes of Israel, will I put my name for ever;" — 2 Kings 21:7 (ASV)

A graven image of the grove. — The graven image of the Asherah (2 Kings 21:3).

In the house of which the Lord said ... —See 1 Kings 8:16; 1 Kings 9:3. This means that the Asherah was erected within the Temple itself, probably in the holy place—an act which was the climax of Manasseh’s impiety. (Compare 2 Kings 23:4; Ezekiel 43:7; Jeremiah 7:30 and following.)