1 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:
   2 Who can have compassion on the ignorant, and on
  them that are out of the way; for that he himself
  also is compassed with infirmity.
   3 And by reason hereof he ought, as for the people,
  so also for himself, to offer for sins.
   4 And no man taketh this honour unto himself, but he
  that is called of God, as was Aaron.
   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.
   6 As he saith also in another place, Thou art a
  priest for ever after the order of Melchisedec.
   7 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;
   8 Though he were a Son, yet learned he obedience by
  the things which he suffered;
   9 And being made perfect, he became the author of
  eternal salvation unto all them that obey him;
  10 Called of God an high priest after the order of
  Melchisedec.
  11 Of whom we have many things to say, and hard to be
  uttered, seeing ye are dull of hearing.
  12 For when for the time ye ought to be teachers, ye
  have need that one teach you again which be the first
  principles of the oracles of God; and are become such
  as have need of milk, and not of strong meat.
  13 For every one that useth milk is unskilful in the
  word of righteousness: for he is a babe.
  14 But strong meat belongeth to them that are of full
  age, even those who by reason of use have their
  senses exercised to discern both good and evil.

...to Hebrews chapter 6