2 Chronicles 18:2-3

2And some years later he went down to visit Ahab in Samaria, where Ahab sacrificed many sheep and cattle for him and the people with him and urged him to march up to Ramoth-gilead.

3Ahab king of Israel asked Jehoshaphat king of Judah, “Will you go with me against Ramoth-gilead?”

And Jehoshaphat replied, “I am as you are, and my people are your people; we will join you in the war.”