What does Hebrews 5:10 mean?

This verse highlights two important aspects of Jesus' ministry. First, as with any true priest, Jesus was appointed to His role by God. No person can simply declare, "I am a priest," since that task means being a mediator between the people and their deity. Prior Scriptures showed how Christ was placed in His role specifically by God.

The second aspect is the way Jesus' High Priesthood is superior to that of Aaron's. The writer of Hebrews uses the example of Melchizedek to make this point. In all of Israel's history, the roles of king and high priest had been separate. However, as the Old Testament predicted, there was a day when these titles would be merged into one person (Zechariah 6:12–13). In Genesis, Melchizedek is described as both a high priest and as a king (Genesis 14:18). Jesus, as the predicted Messiah, is a high priest as Melchizedek was—one imbued also with kingly authority.

The author of Hebrews knows this is an important point to make and that it needs to be developed further. However, the Jewish Christians he is writing to are in need of yet another warning. The first came in Hebrews 2:1–4, reminding them to be more diligent in their faith. The second came in Chapters 3 and 4, as a warning against disobedience and faithlessness. The upcoming passage, beginning in verse 11, will be an alert against spiritual immaturity.