http://en.wikipedia.org/wiki/Melchizedek

Classical Rabbinical interpretation
In the Midrash, the Rabbis identified Melchizedek with Shem son of Noah. (E.g., Babylonian Talmud Nedarim 32b; Genesis Rabbah 46:7; Genesis Rabbah 56:10; Leviticus Rabbah 25:6; Numbers Rabbah 4:8.) Rabbi Isaac the Babylonian said that Melchizedek was born circumcised. (Genesis Rabbah 43:6.) Melchizedek called Jerusalem “Salem.” (Genesis Rabbah 56:10.) The Rabbis said that Melchizedek instructed Abraham in the Torah. (Genesis Rabbah 43:6.) Rabbi Eleazar said that Melchizedek’s school was one of three places where the Holy Spirit manifested itself. (Babylonian Talmud Makkot 23b.) The Rabbis taught that Melchizedek acted as a priest and handed down Adam’s robes to Abraham. (Numbers Rabbah 4:8.) Rabbi Zechariah said on Rabbi Ishmael’s authority that God intended to bring forth the priesthood through Melchizedek’s descendants, but because Melchizedek blessed Abraham before he blessed God (in Gen. 14:19-20), God brought the priesthood forth from Abraham’s descendants. (Babylonian Talmud Nedarim 32b; see also Leviticus Rabbah 25:6 (crediting Rabbi Ishamel).)

Rabbi Judah said in Rabbi Nehorai's name that Melchizedek’s blessing yielded prosperity for Abraham, Isaac, and Jacob. (Genesis Rabbah 43:8.) Ephraim Miksha'ah the disciple of Rabbi Meir said in the latter's name that Tamar descended from Melchizedek. (Genesis Rabbah 85:10.)

Rabbi Hana bar Bizna citing Rabbi Simeon Hasida identified Melchizedek as one of the four craftsmen of whom Zechariah wrote in Zechariah 2:3. (Babylonian Talmud Sukkah 52b; see also Song of Songs Rabbah 2:33 (crediting Rabbi Berekiah in the name of Rabbi Isaac).) The Talmud teaches that David wrote the Book of Psalms, including in it the work of the elders, including Melchizedek (in Psalm 110). (Babylonian Talmud Baba Batra 14b-15a.)

The Zohar finds in “Melchizedek king of Salem” a reference to “the King Who rules with complete sovereignty,” or according to another explanation, that “Melchizedek” alludes to the lower world and “king of Salem” to the upper world. (Zohar 1:86b-87a.)

[edit] The Melchizedek Priesthood and Christianity
Main article: Melchizedek Priesthood (Christianity)
Christians believe that Jesus is the Messiah spoken of as "a priest forever in the order of Melchizedek" (Ps. 110:4), and so Jesus plays the role of High Priest once and for all. Jesus is considered a priest in the order of Melchizedek because, like Melchizedek, Jesus was not a Levite, and thus would not qualify for the Levitical priesthood (Heb. 7:13-17).

[edit] Latter-day Saint Beliefs Concerning Melchizedek
The Book of Mormon of The Church of Jesus Christ of Latter-day Saints describes the work of Melchizedek in Salem in Alma 13:17-18. According to Alma, Melchizedek was King over the wicked people of Salem, but because of his righteousness, his people repented of their wickedness and became a peaceful city.

Also, in Joseph Smith's translation of the Bible, Melchizedek is described as "a man of faith, who wrought righteousness; and when a child he feared God, and stopped the mouths of lions." Because of his fear of God, Melchizedek was "ordained an high priest." The Translation also describes Melchizedek as establishing peace in his city and being called "the king of heaven" and "the King of peace" (JST Bible Gen 14:25-40).

Other Latter-day Saint views on Melchizedek closely match the King James Bible. They focus heavily on Melchizedek as having the Melchizedek Priesthood named after him.

[edit] Shem and Melchizedek
Shem lived five hundred years after fathering Arkpasad, and then died at the age of six hundred (Gen. 11:10, 11). Therefore, his death took place thirteen years after the death of Sara (1881 B.C.E.) and ten years after Rebeca and Isaac married (1878 B.C.E.) In that light, it has been opinioned that it is possible that Shem might have been Melchizedek (which does translate to King of Righteousness), the priest-king to whom Abraham paid tithes (Gen 14: 18-20). However the Biblical records does not say this, the author of Hebrews (possibly St. Paul) points out that there existed no other genealogical records nor any other data on the life of Melchizedek, so he can be said to be an archetype of Jesus the Christ who is now the eternal Priest and King.

[edit] Gnostic Revelations
A collection of early Gnostic ????s found in 1945, known as the Nag Hammadi Library, contains a tractate pertaining to Melchizedek. Here it is revealed that Melchizedek is Jesus Christ[8]. Melchizedek, as Jesus Christ, lives, preaches, dies and is resurrected.

[edit] Confusion over Melchizedek's lineage
See also: List of people who have claimed to be immortal
Hebrews 7:3 creates some confusion between denominations regarding Melchizedek's nature and background. This is how it stands in the KJV, describing Melchizedek as:

"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."

Different denominations interpret this in vastly different ways. Some say that Melchizedek is literally like the Son of God (or even is the Son of God) in that he has no father or mother. Others say that he has been adopted into Christ's lineage through the Lord's suffering, [9] still others claim that the verse has been mistranslated, and that the Priesthood Melchizedek held is what is without lineage, not Melchizedek. [10] Others claim that the verse merely represents Melchizedek's not being a priesthood holder because of lineage (i.e. "without descent" meaning not a descendent of Levi as required by Mosaic Law.)[11]

The Book of the Bee, a Syriac text, also offers insights contrary to Melchizedek's purported immortal nature:

"NEITHER the father nor mother of this Melchizedek were written down in the genealogies; not that he had no natural parents5, but that p. 34 they were not written down. The greater number of the doctors say that he was of the seed of Canaan, whom Noah cursed. In the book of Chronography, however, (the author) affirms and says that he was of the seed of Shem the son of Noah. Shem begat Arphaxar, Arphaxar begat Cainan, and Cainan begat Shâlâh and Mâlâh, Shâlâh was written down in the genealogies; but Mâlâh was not, because his affairs were not sufficiently important to be written down in the genealogies. When p. 35 Noah died, he commanded Shem concerning the bones of Adam, for they were with them in the ark, and were removed from the land of Eden to this earth. Then Shem entered the ark, and sealed it with his father's seal, and said to his brethren, 'My father commanded me to go and see the sources of the rivers and the seas and the structure of the earth, and to return.' And he said to Mâlâh the father of Melchizedek, and to Yôzâdâk his mother...."[12]

[edit] Representative of the priestly line
In some translations, Psalms names Melchizedek as representative of the priestly line through which a future king of Israel's Davidic line was ordained. Alternatively, it may be more accurate to treat this term as an agglutinated improper noun, to be translated as rightful king rather than left as Melchizedek; this interpretation is taken by some modern translations, such as the New JPS Tanakh.