Ramban, on Gen 14:18

“But Melchisedech the king of Salem, bringing forth bread and wine, for he was the priest of the most high God,”

“AND MELCHIZEDEK KING OF SALEM. This is Jerusalem, just as it is said, In Salem is set His tabernacle. In the days of Joshua, its king was also called Adoni-zedek. Since time immemorial the nations knew that this place, which was the choicest of all places, is in the center of the inhabited region. Or perhaps they knew of its superiority by tradition, i.e., that it is exactly opposite the Heavenly Sanctuary, where the Divine Glory of the Holy One, blessed be He, who is called Tzedek (Righteousness) abides., literally, “My king is righteousness.” In Bereshith Rabbah [we find that Jerusalem is called Tzedek because] “this place makes its inhabitants righteous. And Melchizedek means ‘the lord of Zedek.’ Jerusalem is called Tzedek, as it is said, ‘Tzedek’ (Righteousness) lodged in it.” AND HE WAS PRIEST OF G-D THE MOST HIGH. This is stated in order to inform us that Abraham would not give a tithe to the priest of other gods, but since he knew that he was a priest of G-d the Most High, he gave him the tithe as an honor to G-d. He alluded to Abraham through this episode that the House of G-d will be there, and there his descendants will bring the tithe and the Heave-offering, and there they will bless the Eternal. Now according to the opinion of our Rabbis who say that Melchizedek was Shem, the son of Noah, we must say that he left his country in the east and came to Jerusalem to worship the Eternal. He became the people’s priest of G-d the Most High since he was the honored one among their father’s brothers, as Jerusalem was ever in the boundary of the Canaanites. Now Rashi wrote above, “And the Canaanite was then in the land. They were gradually conquering the land of Israel from the descendants of Shem, the ancestor of Abraham, for it had fallen to the share of Shem when Noah apportioned the earth among his sons, as it is said, And Melchizedek king of Salem.” This is not correct because the boundary of the Canaanite was from Sidon,, 10:19. which includes all of the land of Israel. The boundary of the children of Shem, on the other hand, was to the east of Mesha,, Verse 30. far from the land of Israel. But if Noah apportioned the countries among his sons and gave Shem the land of Israel, it would be similar to the case of a person who apportions his goods by word of mouth. Meanwhile, the children of Canaan, [who were the descendants of Ham], settled there until the time came when G-d caused the seed of His friend Abraham. to inherit it, as I have already mentioned. AND HE WAS PRIEST OF G-D THE MOST HIGH. Since there were, among all nations, priests serving the angels called eilim (the mighty ones) — even as it is said, Who is like unto Thee ‘ba’eilim’ (among the mighty) — the Holy One, blessed be He, is called G-d the Most High, the purport thereof being “the Mighty One, Who is Supreme over all,” as in the verse, It is ‘le’eil’ (the power of) my hand. Now Melchizedek did not mention the Eternal, whereas Abraham said, the Eternal, G-d of the Most High.”

Imported from an open dataset — not yet checked against the printed edition.