1 Kings 11:4

when Solomon was old At least half of the king's reign was over before the Temple and the king's house and the other buildings were completed. It was therefore in the latter half of his reign, and probably towards the close of that, when the influence of his wives gained undue sway over him.

perfect with the Lord i.e. Completely devoted to His service, see note on 1 Kings 8:61. Solomon has described the state in his prayer (1 Kings 8:61) -to walk in His statutes, and to keep His commandments." The language of the verse indicates, not that Solomon forsook for himself the worship of Jehovah, but that he was less earnest about it, and allowed side by side with it the temples of heathen gods to be erected, and their worship to be something more than tolerated, even perhaps abundantly supported from his means. As it is said below in 1 Kings 11:6, -he went not fully after the Lord."