Melchizedek

Melchizedek was the priest-king of Salem who lived during the time of Abram and at that time was one of the kings involved in the war against Sodom and Gomorrah. Melchizedek was the first of the priestly Order of Melchizedek (of which is an eponym of him), the alternate order of priests (asides from priests descending from Levi) of priest-kings in which Jesus was a part of.

Biography
Melchizedek's name literally means "king of righteousness". His title as King of Salem, literally denoted the title to be "King of Peace".

In the Book of Genesis, Melchizedek was the king of the city of Salem, that had been under the reign of Kedorlaomer, until an alliance of cities rebelled. While it was not officially documented in the Bible that Melchizedek was fighting in the war, it is known that he was present after Abram rescued Lot and defeated the opposing army.

After Abram had rescued had defeated Kedorlaomer and his allies, multiple kings came and met with Abram. Melchizedek was at the meeting in which he had brought bread and wine and was to serve as God's priest. Melchizedek then blessed Abram for his contributions to defeating Kedorlaomer. He also praised God for delivering the enemies under Abram, and as result of these blessings Abram gave a tenth of his property to the priest-king

Identity
Melchizedek is described to being without a father or mother, or even a genealogy. This may indeed refer to that Melchizedek has no recorded genealogical record to attribute parenthood or family lineage, or perhaps could even refer to a spiritual embodiment of Jesus Christ Himself.

The argument for a pre-incarnate Jesus Christ being Melchizedek falls primarily in the attributes ascribed to each that they share and because the amount of comparison by the author of Hebrews. The interaction of Melchizedek with Abram early on can be symbolism of Jesus and the Hebrew Nation of Israel that descended from Abram. Also Melchizedek brought bread and wine as food and refreshment, the same food Jesus gave to his Apostles to represent his body and blood. He was also the King of Jerusalem, which would be the city that would hold the Temple (which was also typology for Jesus's body), where he would die, and the same name for the city of Heaven (New Jerusalem) after his return.

Others say that Melchizedek was Shem as this has more realism and it would be unnecessary for the Son Jesus to be pre-incarnate. Very old ancient sources from Jewish, if not Hebrew scholars associate Melchizedek as Shem. This explanation also can make Melchizedek eligible in that his lifespan was long enough to be considered "indestructible".

The actual identity of Melchizedek is unknown. Some Christians believe that he may be a pre-incarnate version of Jesus Christ, Noah's son Shem, or simply a unique individual of his own. If he was his own individual then Melchizedek would be similar to a prophet or a Levitical High Priest in that he received a special designation of role by God. This role would have had immense responsibility and privilege in the level of interaction with God, and being a mediator for humans to God. Melchizedek being his own person may have been created simply to establish the order, bestow blessings onto Abram, develop Jerusalem into an early archetypical city, and provide indirect symbolic prophecies to Jesus.

The Order of Melchizedek
Melchizedek being a priest was the founder of the Order of the Melchizedek, consisting of himself and Jesus. The Order of Melchizedek is first mentioned by David in the Book of Psalms proclaiming that Jesus would be eternally apart of the Order, and was sworn by an oath. The only other priestly order, was that of Tribe of Levi, in which did not descend from Melchizedek, but from Abraham. It was necessary for Levi and his priesthood to not have descended from Melchizedek, because only with an entirely different priesthood not based on ancestry, could've the law been changed.

Therefore, Jesus could've only been of Melchizedek's priesthood, in order for priestly regulations to exempt and have been allowed to provide Salvation. It is extremely unlikely that there were any other members of the Order before Jesus, because the membership requirements call for having an "indestructible life" a king and priest hybrid. In addition no one from the Tribe of Judah other than Jesus was a priest. Since Jesus is immortal he did not die compared to other priests and high priests. Because of this the Priesthood of Christ is permanent, rather than being dependent on the human High Priest and those of Levi's Tribe to continue it.