Calvin has a great deal to say about Christ's office as king and prophet, but he is nevertheless clear that Christ's work as priest is the foundation to a proper understanding of his role as Mediator. In the Institutes, he argues that Christ became incarnate, according to the Scriptures, “to restore the fallen world”; and in this context, Calvin means by restoration that “[Christ] was appointed by God's eternal plan to purge the uncleanness of men; for shedding of blood is a sign of expiation.” If we are to understand Christ's purpose, we must begin with his offer of himself through his death to reconcile the Church to God; that is, we must begin with his work as priest. It is only by means of this reconciliation that a way is open for the broader covenant relation between God and the Church. Through his priestly work, Christ opens the way for his work as prophet and king.

This centrality of the sacrificial work of Christ was evident in the Old Testament history, examined in the preceding chapter. We saw at the very beginning of the story that there was, in fact, a history of the Church in its covenant relationship with God only because of God's effective intention to reconcile Godself with God's Church, a reconciliation tied to an expiatory sacrifice. Abraham knew, Calvin concludes at one point, that he would have no access to God apart from such a sacrifice.