It is official membership community. When the world divided into nations, citizenship became the certified recognition of privilege and accountability to the laws and leaders of the nation granting it. Paul invites Christians to think of membership in God’s kingdom in the same way-a relationship of privilege and responsibility. This latter citizenship supersedes and qualifies all other memberships so that the Christian, while loyal to the state (Rom 13:1), is not unconditionally so.
When the responsibilities of national citizenship conflict with biblical standards for behavior or belief, the kingdom citizen owes primary loyalty to God. Defining those conflicts and working out their solution is the ongoing task of Christian social ethics.
PHILIPPIANS 3:20 – But our citizenship is in heaven, and form it we await a Savior, the Lord Jesus Christ.