“Just who was Melchizedek? In Genesis it says he was ‘king of Salem’. But in Psalm 110, it says he was a priest. Please explain.”
When Abraham returned (in victory) from the battle of the kings (in which he rescued Lot), he was met by “Melchizedek king of Salem. . . now he was a priest of God Most High” (Genesis 14:18). Reference is made to him again Psalm 110:4, “the he LORD has sworn and will not change His mind, ‘You are a priest forever According to the order of Melchizedek’”. This was a prophecy of the Christ, as Hebrews 5:5 – 10 shows.
The priesthood of Melchizedek was not based on the law, or on genealogy (as was the case of Aaron and the tribe of Levi). Although he would not qualify to be a priest under the law given to Israel through Moses, God made him “a priest perpetually” (Hebrews 7:3). He was the “king of Salem”, which means the ruler of the city of Jerusalem. He was also “a priest of God Most High”. So he was both king and priest. This was prophetic, for Christ was (and is) prophet, priest and king. God foretold that Christ would be a prophet like Moses (Deuteronomy 18:18, 19), a priest like Melchizedek (Hebrews 7:17) and a king like David (Psalm 89:3, 4; 1 Timothy 6:15).