This was mentioned before, (1 Kings 14:30,) and therefore may seem to come in here improperly, because the historian is not speaking of Rehoboam, but of his son Abijam. Bochart thinks that Rehoboam stands here for the son of Rehoboam. But the meaning of these words seems rather to be, that though God was pleased, for David's sake, to continue a lamp, that is, a successor, to him in Jerusalem; yet these successors were vexed with continual wars, as appeared both in the reign of Rehoboam and of Abijam, and did not enjoy their kingdom peaceably.
Related Commentaries of 1 Kings 15:6
1 Kings 15:6
6 And there was war between Rehoboam and Jeroboam all the days of his life.