Hebrews 5:5
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. 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.
Christ did not glorify, appoint, or exalt Himself to be made High Priest, but was called, appointed, and set apart to that office by God the Father. The Father appointed Him to the priesthood by declaring Him His Son, His only begotten Son. As with Aaron, no one takes this honor to himself, but only one who is called of God. He was appointed by God as Son and as priest forever after the order of Melchizedek.
He set aside His royal position and was taken from among men, taking human nature, bone of bone and flesh of flesh, becoming human for humanity's sake so He could understand human temptation. His divine authority was joined to His humble life among humanity, and to Him was given the prerogative of approaching God in both human and divine nature as the only One who in humanity could with hope approach God. His appointed work was not self-glorification but service to fellow human beings, and His divine appointment qualified Him to be High Priest and Advocate and to serve as an example to the human family.
As High Priest ordained for men in things pertaining to God to offer gifts and sacrifices for sins, He has compassion on the ignorant and those out of the way, having been tempted in all points as the human family is yet without sin. In the days of His flesh He offered prayers and supplications with strong crying and tears to Him who could save Him from death and was heard because of His reverence, and though a Son He learned obedience by suffering and being made perfect became the author of eternal salvation to all who obey Him, knowing how to succor those beset by the powers of darkness. No position or authority gives favor with God; all must come only through the chosen Mediator who knew no sin and in whom no guile was found, who bore the penalty of sin and by His offering of infinite value redeemed the race. Through His grace people may render perfect obedience to God's law and obtain eternal life, and sinful repentant human beings may be received by the Father, clothed with the robe of righteousness, offered sanctification by grace, made obedient sons and daughters of God, and become members of the royal family.
The verse states the only conditions of salvation, requiring true obedience that softens and subdues the heart in God's appointed way by becoming as little children in humility, willing to learn every lesson of obedience and to work the works of God. It leaves no room for entertaining the idea of lifting up or casting down at pleasure, for without this God cannot accept the labors nor save.