In this passage our writer introduces the central theme of his sermon, namely, Christ the faithful and merciful high priest after the order of Melchizedek. First, he defines the qualities of a high priest: function, v1; sympathy, v2-3; and authorization, v4. These qualities are then applied to Christ, v5-10. In v5-6, Christ's call to the priesthood is supported from scripture. v1-4. The writer wants to show that Jesus is genuinely a high priest, although far superior to any of the descendents of Aaron, and is therefore, someone we can rely on to speak for us before the throne of God's grace.
 v1. In the opening verse our writer defines the prime function of a high priest who is of the order of Aaron. Aaron was the brother of Moses and was the first high priest of Israel. The priestly function is to "represent men in matters for which they are responsible before God". In particular, it is to make representation on behalf of the sin of the people. The high priest is to make sin offerings to God for the people, of course, this function corresponds with Christ's sacrificial function.
v2-3. The second characteristic of a high priest is his empathy with sinners, a characteristic which Christ exhibits. A high priest acts with moderation, he restrains his judgment toward those he serves because he shares the same weakness that they share. This is why the earthly high priest must offer a sin offering for himself as well as the people.
v4. The final characteristic of the high priest is that he is called by God. A high priest is appointed by God. The writer could have, at this point, outlined how the choice of high priest in Israel had turned into a political appointment and had been virtually invalid since the monarchy, but he is primarily concerned to align this characteristic with Christ's divine appointment.
v5. The writer now deals with the qualifications of Christ, v5-10. In v5-6 he compares the appointment of Aaron with Christ. Initially, to make this point, our writer draws on the teaching of Psalm.2:7; "You are my Son, this day have I begotten you". Our author wants to establish that Jesus was appointed to the position of High Priest by God the Father. The "this day" is most likely referring to the day of Christ's enthronement - the day when Christ was publicly exalted in his death, resurrection and ascension, Ac.2:36. In that day he was the "coming Son of Man", coming in the sense of proceeding to the throne of God to take upon himself authority and might. In that day Christ was proclaimed "Son" of God. Christ is now seated at the right hand of God and is ruling his kingdom; the "Day" has come. God has handed the authority of the kingdom over to his beloved Son, the Messiah, the Son of David.
v6. This now leads our writer into his piece of original theology. He develops this theology from this chapter onward. As the Davidic Messiah, now ruling his kingdom in glory, Jesus is also high priest. In the book of Zechariah the function of priest and king is at times amalgamated. Originally these functions were separate. The priestly service was performed by Aaron and his family, a family not of the House of David; they were Levites. Later in Israel's history the priesthood was limited to the family of Zadok. The writer to the Hebrews has found a Davidic link to the priesthood in Melchizedek. In Genesis 14:18 Melchizedek is described as the king of Salem, ie. Jerusalem. When David takes over Jerusalem as his city, he inherits the priestly authority of Melchizedek. Christ, the Davidic Messiah, therefore fulfills the high priestly role, and he was given this authority when he was proclaimed "Lord and Christ" at his "coming" to the "Ancient of Days", ie. when he took up his seat at the right hand of the Father in heaven.
 The writer of this letter, or better, sermon or homily, has discovered a fascinating piece of theology about Christ. Not only has the Father authorized Jesus as the divine Son of God, the Davidic messiah, but he has also authorized him as the divine high priest. Of course, the priests were not of the house of David, but our writer has discovered that Melchizedek was both a priest and also the king of Jerusalem. When David captured Jerusalem he inherited both the crown and priestly role of Melchizedek. So the Davidic Christ, in his atoning sacrifice upon the cross, now serves as the eternal faithful and merciful high priest who represents lost humanity before the throne of the living God.
As we struggle through life, we are constantly being tempted to abandon our loyalty to Christ. If we do this we are lost. Our only hope is to throw ourselves on Christ's mercy, seeking aid in our strife. The question is, can Christ meet our need? The answer is yes. He is a high priest who is willing to represent us in the presence of the living God, he is a high priest who is well able to empathize with our weakness, and he is a high priest appointed by God the Father himself. Jesus is completely able to help us in our daily life and eternally save us, and this because he has gone before us as the perfect Son of God.
 1. What are the qualifications of a high priest?
2. What does it mean for a high priest to "deal gently with those who are ignorant"?
3. What has Melchizedek got to do with it all?
4. What is Christ's high priestly function and how does it affect us?