2 Chronicles 23:16
And Jehoiada made a covenant between him, and between all the people, and between the king, that they should be the LORD’s people. And Jehoiada made a covenant between him, and between all the people, and between the king, that they should be the LORD’s people.
Jehoiada made the covenant after Joash had been acclaimed king, binding himself, the king, and all the people together in a solemn pledge that they would belong to the Lord. It was a threefold agreement that joined priest, ruler, and nation in the same consecration. The act was a public renewal of allegiance, by which the people placed themselves under God as His own.
That covenant marked a reformation in Judah once Athaliah's corrupting influence had been removed. With her power broken, the temple of Baal was torn down and its priests were destroyed. The covenant therefore sealed a decisive break with idolatry and restored the nation to the worship of the Lord.