"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. As he saith also in another place, Thou art a priest for ever after the order of Melchisedec. Who in the days of his flesh, when he had offered up prayers and supplications with strong crying and tears unto him that was able to save him from death, and was heard in that he feared; Though he were a Son, yet learned he obedience by the things which he suffered; And being made perfect, he became the author of eternal salvation unto all them that obey him; Called of God an high priest after the order of Melchisedec. Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing."
Hebrews 5:5-11, KJV
"For men verily swear by the greater: and an oath for confirmation is to them an end of all strife. Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath: That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us: Which hope we have as an anchor of the soul, both sure and stedfast, and which entereth into that within the veil; Whither the forerunner is for us entered, even Jesus, made an high priest for ever after the order of Melchisedec. For this Melchisedec, king of Salem, priest of the most high God, who met Abraham returning from the slaughter of the kings, and blessed him; To whom also Abraham gave a tenth part of all; first being by interpretation King of righteousness, and after that also King of Salem, which is, King of peace; Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually. Now consider how great this man was, unto whom even the patriarch Abraham gave the tenth of the spoils. And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham: But he whose descent is not counted from them received tithes of Abraham, and blessed him that had the promises. And without all contradiction the less is blessed of the better. And here men that die receive tithes; but there he receiveth them, of whom it is witnessed that he liveth. And as I may so say, Levi also, who receiveth tithes, payed tithes in Abraham. For he was yet in the loins of his father, when Melchisedec met him. If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron? For the priesthood being changed, there is made of necessity a change also of the law. For he of whom these things are spoken pertaineth to another tribe, of which no man gave attendance at the altar. For it is evident that our Lord sprang out of Juda; of which tribe Moses spake nothing concerning priesthood. And it is yet far more evident: for that after the similitude of Melchisedec there ariseth another priest, Who is made, not after the law of a carnal commandment, but after the power of an endless life. For he testifieth, Thou art a priest for ever after the order of Melchisedec. For there is verily a disannulling of the commandment going before for the weakness and unprofitableness thereof. For the law made nothing perfect, but the bringing in of a better hope did; by the which we draw nigh unto God. And inasmuch as not without an oath he was made priest: (For those priests were made without an oath; but this with an oath by him that said unto him, The Lord sware and will not repent, Thou art a priest for ever after the order of Melchisedec:) By so much was Jesus made a surety of a better testament. And they truly were many priests, because they were not suffered to continue by reason of death: But this man, because he continueth ever, hath an unchangeable priesthood."
Hebrews 6:16-7:24, KJV
"But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man. For it became him, for whom are all things, and by whom are all things, in bringing many sons unto glory, to make the captain of their salvation perfect through sufferings . . . Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil . . . For verily he took not on him the nature of angels; but he took on him the seed of Abraham. Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people."
Hebrews 2:9-10, 14, 16-17, KJV
"Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession. For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin."
Hebrews 4:14-15, KJV