2 Kings 11:21

a son of seven years is Jehoash in his reigning.

2 Chronicles 24:1-14

A son of seven years is Joash in his reigning, and forty years he hath reigned in Jerusalem, and the name of his mother is Zibiah of Beer-Sheba.

2 Kings 11:4

And in the seventh year hath Jehoiada sent and taketh the heads of the hundreds, of the executioners and of the runners, and bringeth them in unto him, to the house of Jehovah, and maketh with them a covenant, and causeth them to swear in the house of Jehovah, and sheweth them the son of the king,

2 Kings 22:1

A son of eight years is Josiah in his reigning, and thirty and one years he hath reigned in Jerusalem, and the name of his mother is Jedidah daughter of Adaiah of Boskath,

Treasury of Scripture Knowledge

Summary

Seven years old was Jehoash when he began to reign.

Bible References

General references

2 Kings 11:4
And in the seventh year hath Jehoiada sent and taketh the heads of the hundreds, of the executioners and of the runners, and bringeth them in unto him, to the house of Jehovah, and maketh with them a covenant, and causeth them to swear in the house of Jehovah, and sheweth them the son of the king,
2 Kings 22:1
A son of eight years is Josiah in his reigning, and thirty and one years he hath reigned in Jerusalem, and the name of his mother is Jedidah daughter of Adaiah of Boskath,
2 Chronicles 24:1
A son of seven years is Joash in his reigning, and forty years he hath reigned in Jerusalem, and the name of his mother is Zibiah of Beer-Sheba.