2 Chronicles 18:28

So the king of Israel and Jehoshaphat the king of Judah went up to Ramoth–gilead.

Cross-reference

2 Chronicles 19:2 Historical context

2 Chronicles 19:2 records Jehu's rebuke to Jehoshaphat for allying with Ahab — a direct consequence of the battle begun in 18:28.

1 Kings 22:29-33 is the parallel account of the same battle, showing the events that follow from the decision to go up.