A High Priest must be duly qualified and divinely appointed

5 ^1-3 Note that when a man is chosen as High Priest he is appointed on men’s behalf as their representative in the things of God—he offers gifts to God and makes the necessary sacrifices for sins on behalf of his fellow-men. He must be able to deal sympathetically with the ignorant and foolish because he realises that he is himself prone to human weakness. This naturally means that the offering which he makes for sin is made on his own personal behalf as well as on behalf of those whom he represents.

⁴ Note also that nobody chooses for himself the honour of being a High Priest, but he is called by God to the work, as was Aaron, the first High Priest in ancient times.