I have been reading the Book of Hebrews. Melchizedek is mentioned in only two places in the Old Testament. The first mention is in Genesis 14 telling of Abraham's return after defeating the four kings. He meets Melchizadek who is portrayed as the King of Righteousness, the King of Salem, which could be interpreted "King of Peace." Melchizadek presents wine and bread and serves Abraham. Abraham pays tithes to this priest of the Most High God.
It is noteworthy that wine and bread are the memorials of the sacrifice of Himself that Christ served to his disciples. The second mention is in Psalm 110, which is a Messianic psalm. Herein the Messiah is averred by God to be a priest forever after the order of Melchizadek.
The Hebrew letter, written as the title indicates, to the Hebrews, explains the priesthood of Christ as superior to and superceding the Aaronic priesthood. The writer indicates that Levi paid tithes to Melchizadek through Abraham, honoring him as superior to the Levitical priesthood and since Christ is priest forever after the order of Melchizadek, He has supplanted the law of the priesthood as given to Moses. A superior priest, a superior law: the law of faith, and a once and for all sacrifice for our salvation.
This is much too rich to be dealt with in a blogpost; hence, the purpose here is to encourage you to get your Bible and pursue this truth in depth.
Meeting of Abraham and Melchizadek by Dierec Bouts the Elder, c. 1467
[and Happy Birthday grandson Jamie]