Because that they have forsaken me
My worship, as the Targum; both Solomon and the children of Israel following his example; which is not to be wondered at, considering how prone they always were to idolatry:
and have worshipped Ashtoreth the goddess of the Zidonians, Chemosh the
god of the Moabites, and Milcom the god of the children of Ammon;
of which deities, (See Gill on 1 Kings 11:5) (See Gill on 1 Kings 11:7).
and have not walked in my ways, to do that which is right in mine eyes,
and to keep my statutes and my judgments, as [did] David his father;
the several laws of God relating to religious worship especially, which David was a strict observer of; and therefore Solomon, having such a pattern before him, was the more blameworthy.