1 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;
   2 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;
   3 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.
   4 Now consider how great this man was, unto whom
  even the patriarch Abraham gave the tenth of the
  spoils.
   5 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:
   6 But he whose descent is not counted from them
  received tithes of Abraham, and blessed him that had
  the promises.
   7 And without all contradiction the less is blessed
  of the better.
   8 And here men that die receive tithes; but there he
  receiveth them, of whom it is witnessed that he
  liveth.
   9 And as I may so say, Levi also, who receiveth
  tithes, payed tithes in Abraham.
  10 For he was yet in the loins of his father, when
  Melchisedec met him.
  11 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?
  12 For the priesthood being changed, there is made of
  necessity a change also of the law.
  13 For he of whom these things are spoken pertaineth
  to another tribe, of which no man gave attendance at
  the altar.
  14 For it is evident that our Lord sprang out of
  Juda; of which tribe Moses spake nothing concerning
  priesthood.
  15 And it is yet far more evident: for that after the
  similitude of Melchisedec there ariseth another
  priest,
  16 Who is made, not after the law of a carnal
  commandment, but after the power of an endless life.
  17 For he testifieth, Thou art a priest for ever
  after the order of Melchisedec.
  18 For there is verily a disannulling of the
  commandment going before for the weakness and
  unprofitableness thereof.
  19 For the law made nothing perfect, but the bringing
  in of a better hope did; by the which we draw nigh
  unto God.
  20 And inasmuch as not without an oath he was made
  priest:
  21 (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:)
  22 By so much was Jesus made a surety of a better
  testament.
  23 And they truly were many priests, because they
  were not suffered to continue by reason of death:
  24 But this man, because he continueth ever, hath an
  unchangeable priesthood.
  25 Wherefore he is able also to save them to the
  uttermost that come unto God by him, seeing he ever
  liveth to make intercession for them.
  26 For such an high priest became us, who is holy,
  harmless, undefiled, separate from sinners, and made
  higher than the heavens;
  27 Who needeth not daily, as those high priests, to
  offer up sacrifice, first for his own sins, and then
  for the people's: for this he did once, when he
  offered up himself.
  28 For the law maketh men high priests which have
  infirmity; but the word of the oath, which was since
  the law, maketh the Son, who is consecrated for
  evermore.

...to Hebrews chapter 8