Exodus

And no man taketh this honour unto himself, but he that is called of God, as was Aaron.

Therefore thou and thy sons with thee shall keep your priest’s office for every thing of the altar, and within the vail; and ye shall serve: I have given your priest’s office unto you as a service of gift: and the stranger that cometh nigh shall be put to death.

And did I choose him out of all the tribes of Israel to be my priest, to offer upon mine altar, to burn incense, to wear an ephod before me? and did I give unto the house of thy father all the offerings made by fire of the children of Israel?

For every high priest taken from among men is ordained for men in things pertaining to God, that he may offer both gifts and sacrifices for sins:

So also Christ glorified not himself to be made an high priest; but he that said unto him, Thou art my Son, to day have I begotten thee.