Matthew Henry on 2 Kings 11:17-21

King and people would cleave most firmly to each other, when both had joined themselves to the Lord. It is well with a people, when all the changes that pass over them help to revive, strengthen, and advance the interests of religion among them. Covenants are of use, both to remind us of, and bind us to, the duties already binding on us. They immediately abolished idolatry; and, pursuant to the covenant with one another, they expressed mutual readiness to help each other. The people rejoiced, and Jerusalem was quiet. The way for people to be joyful and at peace, is to engage fully in the service of God; for the voice of joy and thanksgiving is in the dwellings of the righteous, but there is no peace for the wicked.