Jesus is Prophet, Priest and King. John Calvin in the third edition of his Institutes explores all three. But the threefold office of Christ is not first found in Calvin. Jesus is our high priest (Hebrews 8:1) and our King (Acts 17:7, 1 Tim 6:15) and he is the great Prophet (Matthew 13:57). And following the scriptures, the early church fathers expounded upon his three offices. And it was Eusebius in his Ecclesiastical History (1.3.8) who said that Jesus is, “the only high priest of all, and the only king of every creature, and the Father’s only supreme prophet of prophets.”
Calvin said, “Among heretics and false Christians, Christ is found in name only; but by those who are truly and effectually called of God, he is acknowledged as a prophet, king and priest… though little [is] gained by holding the names unaccompanied by a knowledge of the end and use.”
With that warning in mind, The Westminster Shorter Catechism is a good starting place to consider these things:
Q. 23. What offices doth Christ execute as our Redeemer?
A. Christ, as our Redeemer, executeth the offices of a prophet (Deut 18:18, Heb 1:1-2), of a priest (Heb 4:14-15, Heb 5:5-6),and of a king (Is 9:6-7, Lk 1:32-33, John 18:37, 1 Cor 15:25), both in his estate of humiliation and exaltation.
Q. 24. How doth Christ execute the office of a prophet?
A. Christ executeth the office of a prophet, in revealing to us, by his Word (Heb 2:3) and Spirit (1 Peter 1:11), the will of God for our salvation.
Q. 25. How doth Christ execute the office of a priest?
A. Christ executeth the office of a priest, in his once offering up of himself a sacrifice to satisfy divine justice (Acts 8:32-35), and reconcile us to God (Col 1:21-22), and in making continual intercession for us (Heb 9:24).
Q. 26. How doth Christ execute the office of a king?
A. Christ executeth the office of a king, in subduing us to himself, in ruling and defending us (Col 1:13), and in restraining and conquering all his and our enemies (Col 2:15).