Chapter 23 describes the role of the civil authorities in relation to the church. Governments are ordained by God to maintain justice and peace and to punish evil doers. The civil magistrate has no right to interfere with the preaching of the word of God or administration of the sacraments. The power of the keys is reserved exclusively to church authorities. Nevertheless, the civil magistrate has a duty to preserve church unity, suppress heresy, and prevent corruption and abuse within the church. To fulfill these obligations, the magistrate has authority to convene synods and ensure that its deliberations are agreeable to "the mind of God."