Albert Barnes Commentary 1 Kings 15:3

"And he walked in all the sins of his father, which he had done before him; and his heart was not perfect with Jehovah his God, as the heart of David his father." — 1 Kings 15:3 (ASV)

He walked in all the sins of his father—yet Abijam prepared precious offerings for the temple service (1 Kings 15:15), probably to replace vessels which Shishak had carried off, and in his war with Jeroboam, he professed himself a faithful servant of Yahweh (2 Chronicles 13:10–12).