Apostol § 311

Brethren, seeing that we have a great High Priest that is passed into the heavens, Jesus the Son of God, let us hold fast our confession. For we do not have a High Priest which cannot be touched with the feeling of our infirmities, but was in all points tempted H like as we are, yet without sin. Let us therefore come boldly unto the throne of grace, that we may obtain mercy and find grace to help in time of need... For every high priest taken from among men H is appointed for men in things pertaining to God, that he may offer both gifts and sacrifices for sins. He can have compassion who are and astray, on those ignorant going since he himself is also beset by weakness. Because of this he is required, as for the people, so also for himself, to offer for sins... And no man takes this honor unto himself, but he that is called by God, as was Aaron. So also Christ did not glorify Himself to become High Priest, but He that said unto Him: ‘Thou art My Son, today have I begotten Thee.” As He saith also in another place: “Thou art a priest for ever after the order of Melchizedek” ...