Hebrews 5:10

It was for this purpose, that He might be a merciful and faithful high priest, that God appointed Jesus as our High Priest. The writer developed the subject of the order of Melchizedek later (ch. 7).

Jesus Christ is not only superior to angels (Hebrews 1:5-14) and Moses (Hebrews 3:1-6) but also Aaron (Hebrews 5:1-10).

"The orientation given to the exposition is intensely practical. The solidarity of the heavenly high priest with the community in its weakness provides a strong motivation for earnest prayer. The demand to draw near to the one who is thoroughly familiar with the human condition, who suffers with their suffering, and who is therefore qualified to mediate renewed strength (Hebrews 4:15-16) is an appeal to recognize the importance of prayer in the rhythm of Christian life." [Note: Lane, p. 123.]