The first thing we are taught in Hebrews 2:17 is that The Lord Jesus Christ was apointed by God to be our great High Priest. The word, "wherefore", does not refer so much to what Paul has said as it does to what he is about to say. He has shown us how that Christ is superior to angels, and that he came into the world, not to redeem fallen angels, but to redeem fallen men. And now he is about to show us how that Christ is superior to Moses, Joshua, and Aaron as the almighty, effectual Savior of his people. He begins by telling us that it was necessary for Christ to be made like those people whom he came to save so that he might be our great High Priest in things pertaining to God.
AN APPOINTED PRIESTThe Lord Jesus did not assume this office on his own. He was called, appointed,and anointed to it by God the Father in the covenant of grace before the world began (Heb. 5:1, 4-5). Christ was made a Priest by the oath of God himself (Psa. 110:4). Yet, the Son of God voluntarily agreed to become our Priest and to fulfil all that God required to reconcile us unto himself. He said, "'Sacrifice and offering thou wouldest not.' The sacrifices of slain beasts offered by sinful men cannot atone for human sin. 'But a body hast thou prepared me,' in the everlasting covenant of grace, which I am ready, at the appointed time, to assume and to offer up as a sacrifice to Divine justice for the sins of my people" (Heb. 10:5). "These eternal decrees and mutual transactions," wrote John Gill, "are the basis and foundation of Christ's priesthood, and made it sure and certain."
THE OLD TESTAMENT PROPHECIESIn the prophetic Scriptures of the Old Testament Christ was spoken of as a priest. The promised Messiah of the Old Testament was to be One who would be a prophet like Moses, a King like David and a Priest like Melchizedek (1 Sam. 2:35; Psa. 110.4; Zech. 6:12-13). In addition to the plain prophecies that Christ should be a Priest, his priestly work is spoken of in many of the Old Testament scriptures (Isa. 53:10, 12; Ezek. 9:3; Dan. 10:5).
OLD TESTAMENT TYPESThe priesthood of Christ was also foreshadowed by the typical priests of that dispensation. There never was but one Priest by whom transactions might be made with God. That Priest is Christ our Lord. All others appointed to the priestly office were called priests, because they represented, pointed to, and foreshadowed him, the true Priest. Only Christ could atone for sin, turn away the wrath of God, and bring men to God in reconciliation.