In 11:17—12:21 we have an account of the reign of Joash (Jehoash) over Judah.
Jehoiada the high priest made a covenant between Jehovah and the king and the people that they would be Jehovah's people. He also made a covenant between the king and the people. Then all the people went to the house of Baal, broke it into pieces, shattered Baal's altars and images to pieces, and slew the priest of Baal (11:17-18).
At the age of seven, Joash was enthroned by the people with rejoicing (vv. 19-21). Since Joash was still a boy, he was greatly helped by the high priest.
Joash began to reign over Judah from the seventh year of Jehu and reigned for forty years in Jerusalem (12:1).
Joash did what was right in the sight of Jehovah all the days in which Jehoiada the high priest instructed him. However, the high places were not removed, and the people still sacrificed and burned incense in the high places (vv. 2-3).
Joash repaired the house of God with the offerings by the people under the management of the priests and the servants of the king, those who were faithful. But the money from the trespass offerings and the money from the sin offerings were for the priests (vv. 4-16).
Hazael king of Syria came up to seize Jerusalem. Joash king of Judah sent him all the things which had been sanctified by his fathers and by himself with all the gold in the treasuries of the house of Jehovah and the house of the king, and Hazael departed from Jerusalem (vv. 17-18).