1 Kings 14:25 - Joseph Benson’s Commentary on the Old and New Testaments

In the fifth year of King Rehoboam Presently after his and his people's apostacy, which was not till his fourth year; while apostate Israel enjoyed peace, and some kind of prosperity; of which difference two reasons may be given: first, Judah's sins were committed against clearer light, and more powerful means and remedies of all sorts, and therefore deserved more severe and speedy judgments. Secondly, God discovered more love to Judah in chastising them speedily, that they might be humbled, reformed, and preserved, as it happened; and more anger against Israel, whom he spared to that total destruction which he intended to bring upon them. Shishak He is thought to be Solomon's brother-in-law; but how little such relations signify among princes, when their interest is concerned, all histories witness: besides, Rehoboam was not Solomon's son by Pharaoh's daughter, and so the relation was in a manner extinct. Came up Either from a desire to enlarge his empire; or by Jeroboam's instigation; or from a covetous desire of possessing those great treasures which David and Solomon had left; and, above all, by God's providence disposing his heart to this expedition, for Rehoboam's punishment.