But Josaphat the son of Asa began to reign over Juda in the fourth year of Achab king of Israel.

And Jehoshaphat son of Asa hath reigned over Judah in the fourth year of Ahab king of Israel,

And Jehoshaphat, the son of Asa, became king over Judah in the fourth year of Ahab's rule over Israel.

Yet truly, Jehoshaphat, the son of Asa, had begun to reign over Judah in the fourth year of Ahab, the king of Israel.

The writer returns to the history of the kingdom of Judah (connect this verse with 1-Kings 15:24), sketching briefly a reign much more fully given by the writer of Chronicles 2 Chr. 17-20. Compare also the marginal references.

And Jehoshaphat the son of Asa began to reign over Judah in the fourth year of Ahab king of Israel. And as Ahab reigned twenty two years, 1-Kings 16:29, Jehoshaphat must reign about eighteen years with him, and seven years after him.

Jehoshaphat's reign appears to have been one of the best, both as to piety and prosperity. He pleased God, and God blessed him.

Reign of Jehoshaphat of Judah. - The account of this in the books before us is a very condensed one. Beside the two campaigns in which he joined with Ahab and Joram of Israel against the Syrians and Moabites, and which are described in the history of the kingdom of Israel (1 Kings 22:1-35 and 2 Kings 3), we have simply a short notice of his attempt to restore the trade with Ophir, and a general statement of the spirit of his reign; whereas we learn from the extract preserved in the Chronicles from the annals of the kings, that he also carried on a victorious war against the Edomites and Ammonites (2 Chron 20), and did a great deal to promote the spread of the knowledge of the law among his people, and to carry out the restoration of a better administration of justice, and to improve the condition of the army (2-Chronicles 16:1-14 and 2-Chronicles 19:1-11).

Of Ahab - Who reigned twenty two years; therefore he reigned about eighteen years with Ahab.