(Revisiting a topic that has been discussed here previously.)
When Calvin discusses the differences between the two “kingdoms” or “governments” ruled by God in Institutes 4.20.2, he makes one “spiritual” and “inward,” and connects it to the “heavenly kingdom,” and the other “external,” and connects public worship with the latter and with civil justice. “Civil government,” he says, has duties vis-a-vis the outward expression of the Christian faith that Calvin describes as “fostering,” “maintaining,” and “defending,” in addition to its responsibility for keeping the peace between men and ensuring that people live according to “civil justice.” Though these two realms (inner and outer, spiritual and civil, heavenly and earthly), according to Calvin, are distinct from one another they are not in actual fact, and so ought not to be in practice, opposed to one another.
But as we lately taught that that kind of government [i.e., civil government] is distinct from the spiritual and internal kingdom of Christ, so we ought to know that they are not adverse to each other. The former, in some measure, begins the heavenly kingdom in us, even now upon earth, and in this mortal and evanescent life commences immortal and incorruptible blessedness, while to the latter it is assigned, so long as we live among men, to foster and maintain the external worship of God, to defend sound doctrine and the condition of the Church, to adapt our conduct to human society, to form our manners to civil justice, to conciliate us to each other, to cherish common peace and tranquillity.
The reason for harmonizing these two aspects of man’s life is because the “kingdom of God,” though of heavenly origin, does not do away with this present life. For Calvin, it is precisely because we are pilgrims right now that we stand in need of such helps. That is, in his view the magistrate’s cura religionis is not opposed to the idea of pilgrimage but is actually adapted to it.
All these I confess to be superfluous, if the kingdom of God, as it now exists within us, extinguishes the present life. But if it is the will of God that while we aspire to true piety we are pilgrims upon the earth, and if such pilgrimage stands in need of such aids, those who take them away from man rob him of his humanity.