Abram (later called Abraham) was blessed by Melchizedek, the King of Salem and priest of the Most High God, who presented him with loaves of bread as wine was being served and, in return, Melchizadek received tithes from Abram, which was a tenth of all the goods he had recovered.
(Genesis 14:18-20)
18. And Melchizedek, king of Salem, brought forth bread and wine: and he was the priest of the most high God.
19. And he blessed him, and said, Blessed be Abram of the most high God, possessor of heaven and earth:
20. And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all.
Reference is made to him in Psalms 110:4, where the victorious ruler, Abram, is declared to be “priest forever after the order of Melchizedek”.