What does Hebrews 5:1 mean?

Chapter 4 closed with a description of Jesus' connection to mankind. His full humanity allows Him to understand what human temptation is like. So, as this verse continues to explain, He is able to act as a proper high priest. This role requires the priest to communicate between God and men. This includes making offerings for sin.

Earlier portions of Hebrews explained that Messiah had to be human, not merely some angelic being (Hebrews 2:17). One reason for this is the issue explored between the end of chapter 4 and the beginning of chapter 5. In order for Messiah to truly represent humanity, as a priest, He had to be human. Without humanity, He would not be able to sympathize with human weaknesses (Hebrews 4:15), would not be able to act as a mediator between God and men (1 Timothy 2:5), and would not be someone we could approach in confidence (Hebrews 4:16).

The idea of being "appointed" in this verse is important. A true priest is not someone who simply decides to take on the task. They have to be selected for that role by God. One cannot simply declare, "I'm a priest" and make it so. This is even more critical for a high priest, who acts on behalf of all people. Jesus' appointment to the role of our ultimate High Priest will be further explained using examples from the Old Testament, such as Aaron and Melchizedek. This verse summarizes the details seen in verses 4, 5, and 6.