Perhaps we are all familiar with the Reformed way of categorizing the work of Christ into the three offices of Prophet, Priest and King. Thomas Goodwin has some beautiful insight into the relation of Christ’s headship over the Church to the three offices.
I have often had many discussions with myself, whether that this relation of headship should not import some distinct office from that of king, priest, and prophet, to which three all divines do reduce the offices of Christ. But I have at last resolved my thoughts thus: that this relation of headship doth import all his offices, but with that peculiarness, and with that eminency, as no other relation is Scripture doth. For -
First, to begin with his kingly office; there is this difference between a king and a natural head of a body, that a king ruleth only externally by commands, and by laws, and by proclamations declared; but the rule of a head is natural. Therefore now, if you reduce it to the kingly office of Christ, it is with an eminency, with a peculiarity. It is our advantage that we are not ruled by Christ as a king simply considered, so far as that similitude will carry it, by external laws revealed, or by way of promises or rewards; but we are ruled by Christ naturally and inwardly, as the members are ruled by the head, which of all rules is the best and most eminent. So that it noteth out the peculiarity of his kingly office.
Secondly, come to his prophetical office. His headship noteth that too, and that with a peculiarity. The head doth not teach the members by outward dictates, or by way of doctrine; but it doth teach the members by way of impression, a secret impression, carrying them on to do the thing teacheth. So Jesus Christ, as a head, doth not only teach by way of doctrine, but by efficacy. I need not write unto you, saith he, for you are all taught of God to love one another. And this is the most glorious teaching in the world.
Thirdly, go to his priestly office, and his headship importeth that too. There are two parts of his priestly office. There is, first, offering of sacrifice; secondly, there is intercession, a pleading of that sacrifice before God for us. And of the two, intercession is the most eminent part of the priesthood of Christ; for that part of his priestly office was resembled by Melchisedec, who, we never read, offered sacrifice, but he blessed Abraham, as Christ doth us from heaven, and now intercedeth for us.
Now, intercession is noted out by headship, for it is natural to the head to speak for us members; the tongue speaks, if speaking will prevent any danger; the head takes care of the members by intercession and by pleading. It noteth out therefore, his priestly office, and that with an eminency and by a peculiarity.
Thomas Goodwin, on Ephesians 1:22, 23 (Sermon XXXVI, Works, Vol. 1)