Joash was seven years old when he became king.
Jehoiada had now got over the harlot part of his work, when, by the death of Athaliah, the young prince had his way to the throne cleared of all opposition. He had now to improve his advantages for the perfecting of the revolution and the settling of the government. Two things we have an account of here: - I. The good foundations he laid, by an original contract, Kg2 11:17.
Commenting on 2 Kings 11:17-21
Seven years old was Jehoash - The first instance on record of making a child seven years old the king of any nation, and especially of such a nation as the Jews, who were at all times very difficult to be governed.
2Ki 11:19-21 And he took the captains, and they brought the king down out of the house of Jehovah, etc. The word יקּח is not to be pressed, but simply affirms that Jehoiada entrusted the persons named with the duty of conducting the king into his palace.
Commenting on 2 Kings 11:19-21