God works in His temporal kingdom by means of vocation; that is, by working through human beings in the ordinary tasks and relationships of earthly life. That Christians have a double life, as citizens in both of God’s kingdoms, is a continual theme in Luther’s writings. Christians are simultaneously saints and sinners. Spiritually, they are clothed in Christ’s righteousness. And yet, they still live in the flesh, where they must struggle against sin and perform good works.
