Genesis 14:20

and blessed be the most high God, which hath delivered thine enemies into thine hand. And he gave him tithes of all. So Melchizedek transmitted to Abram the blessing of God, of the Most Exalted One, of the Founder and Owner of heaven and earth. And, in turn, he praised the Lord, the Exalted One, to whom the victory of Abram must be ascribed. It was a prayer for prosperity and blessing, in beautiful, poetical form. Melchizedek is a type of Christ, The great High Priest of the New Testament, Psalms 110:4, and the entire 7th Chapter of Hebrews is really a commentary on this passage. Abram acknowledged Melchizedek as a priest by giving him tithes of all, Hebrews 7:4. This was the more important transaction at the meeting.