The Lord struck him, i.e. Jeroboam, as appears from the contrary condition of Abijah described in the next verse. Him God might strike, either with vexation and horror of mind; or with some painful and lingering, but incurable, disease, like that of Jehoram, which tormented him two years together, and at last killed him, 2 Chronicles 21:19. He died; not presently, but a year or two after this time.
Related Commentaries of 2 Chronicles 13:20
2 Chronicles 13:20
20 Neither did Jeroboam recover strength again in the days of Abijah: and the LORD struck him, and he died.