Hebrews 7:1-3 (ESV)
For this Melchizedek, king of Salem, priest of the Most High God, met Abraham returning from the slaughter of the kings and blessed him,  and to him Abraham apportioned a tenth part of everything. He is first, by translation of his name, king of righteousness, and then he is also king of Salem, that is, king of peace.  He is without father or mother or genealogy, having neither beginning of days nor end of life, but resembling the Son of God he continues a priest forever.
Some might remember the “slaughter of the kings” and Abraham tithing a tenth of the spoils to Melchizedek, who is perhaps the most enigmatic character of the Old Testament. He occupoies a souple paragraphs, and one is left wondering where did this guy come from? If you are me, you sort of wonder if this man, wasn’t actually a preincarnate theophany of the Son of God. At any rate, you are also left with the notion that the inhabitants of Jerusalem (City of Salem, or City of Peace) were very faithful worshipers of the One True God. Or perhaps it is just that there was a good number of them who were. They had a priest dedicated to His service.
His was a peculiar priesthood. The Aaronic priesthood had an elaborate beginning. It seems before the Aaronic Priesthood, fathers acted as priests for their family. This anarchic approach to worship, though, seems to have led, many different families to worship many different gods and “goat demons” while at the same time perhaps harboring some homage to the God of Abraham. Melchizedek isn’t the only “Priest” that you find though, there was Jethro, Moses’ father inlaw, and even Balam seems to have been a Priest of the Most High God, despite his mercenary tendencies. But Melchizedek is the one. He is chosen to be the type for Christ.
It seems that the rabbi’s must have made much of Melchizedek, Hebrews 7 develops quite a bit of theology around him. Perhaps it is his being mentioned in Psalm 110. He had no beginning, no end He continues a Priest forever. Whether or not Melchizedek was a preincarnate theophany of Christ, it is true of Christ that he continues a Priest forever interceding for us before the throne of the Father day and night, without ceasing. Yes, as a Priest, Christ prays for you! He is without end.