5 So also Christ did not glorify Himself to become High Priest, but it was He who said to Him: “You are My Son, Today I have begotten You.”
Verses 5–10 set forth the call of Christ to the priesthood. The Levitical priesthood had ceased with the change of God’s dealing with Israel, for now God dealt with the church. Christ began His priestly role with appropriate directions from the Father. His priesthood was very distinct from the Levitical priesthood. Christ’s priesthood was superior to theirs.
5 So also
These words connect the sonship of Christ to His priesthood section. As Aaron was a priest, so also Christ was a priest.
Christ did not glorify Himself to become High Priest,
Christ did not assume the High Priest office without the Father’s call for Him to do it. Our Lord did not operate on personal ambition (Jn 8:54). However, it was His glory to be declared Mediator for all mankind. He was a “great High Priest” (He 4:14).
but it was He [Father] who said to Him [Christ]:
Hebrews again quotes Psalm 2:7; the first occurrence was in Hebrews 1:5. This quote establishes Christ’s qualification to be a priest. His role as “Son” wonderfully qualified Him for this High Priest role.
“You are My Son,
The context of Psalm 2 indicates that the role of the Son is as king-son. The Lord was the Davidic heir who was to rule the nations (Ps 2:8). He was the Father’s mediator for those who believe in Him. This was a public announcement of the Messiah to be mediator. His sufficiency to be High Priest lies in His divine nature. It was the dignity of His sonship that gave value to His mediatorship (He 1:2).
Today I have begotten You.”
Christ was the Son from eternity as the only-begotten of the Father. This phrase refers to the Father’s installation or inauguration of the Son’s mediatorship following the resurrection. The resurrection demonstrated that the Father divinely determined what happened.
Christian work is a divine appointment.
Psalm 2 is an exalted view of the Messiah as king-priest. The Father appointed Christ to this task. He fulfilled the will of God in every respect. He was a person of great glory but also of great humility.
It is important to note that “begotten” in this passage has nothing to do with the birth of Jesus into humanity. The timing had to do with His resurrection; He was begotten from the dead. His priesthood began upon His re-entering heaven.