Malchizedek - Mysterious King and Priest

Malchizedek appears in Breishis 14:18, where he comes to greet Avraham after the battle of the 5 kings vs. the 4 kings.  His role is somewhat unclear, but he is clearly someone of great importance.  He is introduced as both King of Shalem and Priest to G-d the Most High.  Some sources say that his actual identity was Shem, son of Noach.  The 3 pesukim concerning Malchizedek are as follows:

יח  וּמַלְכִּי-צֶדֶק מֶלֶךְ שָׁלֵם, הוֹצִיא לֶחֶם וָיָיִן; וְהוּא כֹהֵן, לְאֵל עֶלְיוֹן.

יט  וַיְבָרְכֵהוּ, וַיֹּאמַר:  בָּרוּךְ אַבְרָם לְאֵל עֶלְיוֹן, קֹנֵה שָׁמַיִם וָאָרֶץ.

כ  וּבָרוּךְ אֵל עֶלְיוֹן, אֲשֶׁר-מִגֵּן צָרֶיךָ בְּיָדֶךָ; וַיִּתֶּן-לוֹ מַעֲשֵׂר, מִכֹּל.

This is the only explicit mention of him in the Torah, but there are a lot of midrashic materials about him.  He is the first to refer to G-d as אֵ-ל עֶלְיוֹן, and Avraham is obviously impacted by this because he immediately mirrors Malchizedek's phrasing a few pesukim later:

כב  וַיֹּאמֶר אַבְרָם, אֶל-מֶלֶךְ סְדֹם:  הֲרִמֹתִי יָדִי אֶל-יְהוָה אֵל עֶלְיוֹן, קֹנֵה שָׁמַיִם וָאָרֶץ.


The Rabbis taught that Melchizedek handed down Adam's robes to Abram (Numbers Rabbah 4:8).


Zechariah experienced a vision of "4 craftsmen" appearing to him (Zechariah 2:3):

ג  וַיַּרְאֵנִי יְהוָה, אַרְבָּעָה חָרָשִׁים.

The gemara in Sukkah 52b expounds:

And the Lord showed me four craftsmen. Who are these ‘four craftsmen’? — R. Hana b. Bizna citing R. Simeon Hasida replied: The Messiah the son of David, the Messiah the son of Joseph, Elijah and the Righteous Priest.


In Tehillim 110:4, it states:

ד  נִשְׁבַּע יְהוָה, וְלֹא יִנָּחֵם--    אַתָּה-כֹהֵן לְעוֹלָם;
עַל-דִּבְרָתִי,    מַלְכִּי-צֶדֶק.

4 The LORD hath sworn, and will not repent: 'Thou art a priest for ever after the manner of Melchizedek.'