Hashem has sworn and will not relent, “You are a Kohen forever, after the manner of Melchizedek.” PSALMS 110:4 (The Israel Bible™)
This psalm speaks of the coronation of a king, possibly David. It includes praises and blessings to the king of Israel who rules from Tzion, who will judge the nation, lead the army, and follow in the ways of Hashem. God sees the king as a kind of priest, as he serves the people and represents them to God, much like a priest does in the Beit Hamikdash. The first king-priest lived in the time of Avraham, though he was not from his family. The Bible praises Melchizedek, the great king of Shalem, which is the original name for Yerushalayim. Melchizedek recognizes Avraham’s justice and blesses God in his presence (Genesis 14:18-20).