2 Kings 11:4

11:4 In the seventh year Jehoiada summoned the officers of the units of hundreds of the Carians and the royal bodyguard. He met with them in the Lord’s temple. He made an agreement with them and made them swear an oath of allegiance in the Lord’s temple. Then he showed them the king’s son.

2 Kings 11:21

Joash’s Reign over Judah

11:21 (12:1) Jehoash was seven years old when he began to reign.