Reference

2 Kings 11: 21 - 12:2
Kid's Sunday - Jehoash (Joash), King at 7 Years Old!

21 Seven years old was Jehoash when he began to reign.

12 In the seventh year of Jehu Jehoash began to reign; and forty years reigned he in Jerusalem. And his mother's name was Zibiah of Beersheba.

And Jehoash did that which was right in the sight of the Lord all his days wherein Jehoiada the priest instructed him.