So who, exactly, was Melchizedek.
He ministered to Abram even before God changed his name to Abraham.
Way Old Testament reference.
There isn’t much information about Melchizedek, but I believe he was a pre-figuration of Christ.
Remember with God there is not timeline as we know it.
Jews have universally identified Melchizedek as Shem, son of Noah. Melchizedek is a title that means ‘righteous king’.
Shem and his grandson Eiver taught God’s laws as known to Adam and Noah. The story of Melchizedek is Shem transferring responsibility for teaching God’s will to his descendant the righteous Abraham.
One of the reasons they are called Hebrews (’Ivri’ in the Hebrew language) is because they were associated with the teachings of Eiver.
You are correct re Melchizedek.
“Then King Melchizedek of Salem brought out bread and wine. He was a priest of God Most High. He blessed Abram, and said, “Blessed is Abram by God Most High, maker of heaven and earth. Blessed is God Most High, who has handed your enemies over to you.” Then Abram gave him a tenth of everything.” (Genesis 14:18-20 GW)
See also...
“And from Jesus Christ, who is the faithful witness, and the first begotten of the dead, and the prince of the kings of the earth. Unto him that loved us, and washed us from our sins in his own blood, And hath made us kings and priests unto God and his Father; to him be glory and dominion for ever and ever. Amen.” (Revelation 1:5-6 KJV)
“And hath made us kings and priests unto God and his Father”...I have accepted that commission, ordained not by any man, but by Jesus Christ himself. He gives me the privilege of performing all priestly functions.