This window portrays the offering of bread and wine by Melchisedek, the "King of Salem" and "priest of God Most High" {Genesis 14:18}. This event occurred after the defeat of four enemy kings by Abraham, who was then known as Abram. He and a few of his soldiers may be seen in this window, holding weapons and wearing battle garb. The crowned Melchisedek stands behind a stone altar, elevating his offering. Abraham is down upon one knee, giving the priest-king homage. Before departing, he and his allies will pay a tithe (one tenth of their goods) to Melchisedek {see 14:20}. 

    "Salem" was the first reference to Jerusalem in the Bible. It may be the city seen on the hills in the background. Archaeology attests to its inhabitation more than three millennia before the birth of Christ. It was captured from the Jebusites circa 1000 B.C. by King David {see 2 Samuel 5:6-10}, who made it the capital of the Israelite kingdom and brought the Ark of the Covenant there {see 6:12-17}. 

    Melchisedek's food offering of bread and wine to God bear a prophetic relation to Christ's Last Supper, which as an unbloody food offering was the anti-type of Calvary. This offering also relates to the Mass, in which the Body and Blood of Christ are sacrificed in an unbloody manner under the appearances of bread and wine. 

    Melchisedek was a mysterious figure, with little revealed about him in the Old Testament. Due to the fact that no mention was given in the Scriptures to his birth, death, or genealogy, he was seen as a sort of eternal personage, "a priest forever". Because Abraham, the ancestor of Levi and Aaron and their priestly descendants, payed homage and a tithe to Melchisedek, the latter is seen as a superior priest to those of the Levitical and Aaronite lines. For this reason, the author of the Epistle to the Hebrews (once believed to have been St. Paul) refers to Christ as "high priest forever according to the order of Melchisedek" {Hebrews 6:20; a quote of a Messianic prophecy in Psalm 110:4}. That is, Christ is the eternal Priest, and like Melchisedek is superior to the all the priests who descended from Abraham. 

    The Gentiles who were entering the Faith may not have found this comparison to Melchisedek to be of major importance. However, to the Jews of that day, who were very attached to the sacrificial rites of the Temple and its priests, this was an important aspect of Christ's identity for the epistle's writer to teach in order to win (and keep) converts from that race. 

    Other parallels may be drawn between Melchisedek and Christ. Melchisedek's name is Hebrew for "King of Righteousness", a title also applied to Christ. The Epistle to the Hebrews notes that Melchisedek, as King of Salem (Shalem in Hebrew), is the "King of Peace" (Shalom in Hebrew). In addition, as priest and king, he had a twofold dignity, just as Jesus had two natures: Divine and human, and was also Priest and King. For these reasons, Melchisedek was seen by the early Church Fathers and Christian theologians as a "type" of Christ. 

- From the Roman Canon of the Mass