1 Kings 22:41-50
And Jehoshaphat the son of Asa began to reign over Judah in the fourth year of Ahab king of Israel.
Torrey's Topical Textbook—AKJV

2 Chronicles 17:1-21:1
And Jehoshaphat his son reigned in his stead, and strengthened himself against Israel.
Torrey's Topical Textbook—AKJV