Jehoshaphat began ruling over Judah as coregent with his father Asa (873-870 B.C.). When Asa died, he reigned alone for 17 more years (870-853 B.C.). He concluded his 25-year reign with another period of coregency with his son Jehoram that lasted eight years (853-848 B.C.). For all but Jehoshaphat's first year on Judah's throne, Ahab ruled over Israel. Jehoshaphat became Judah's sole ruler in Ahab's fourth year (v. 41).
Jehoshaphat was one of the eight good kings of Judah and one of the four reforming kings. He was better than his father Asa but not as highly acclaimed by the writers of Scripture as Hezekiah and Josiah, the other reforming kings who followed him years later. Especially in his earlier years Jehoshaphat walked with Yahweh. He removed idolatry from Judah (v. 46) except for the high places (v. 43). Evidently earlier in his reign he removed these (2 Chron. 17:6), but when the people rebuilt them he let them stand (2 Chron. 20:33).
The peace that existed between Israel and Judah (v. 44) gained strength through the marriage of Jehoshaphat's son, Jehoram, and Ahab's daughter, Athaliah (2 Kings 11). A prophet rebuked Jehoshaphat for his alliance with Israel (2 Chron. 19:2).
Edom (v. 47) had been under Judah's control but revolted during Jehoshaphat's reign. It may well have been the Edomites who destroyed his ships at Edom's port of Ezion-geber (v. 48).238
Jehoshaphat submitted to Yahweh's sovereignty, but he relied on human wisdom and resources at crucial moments in his life. This resulted in mixed blessing and discipline for both himself and Israel.