In Genesis 14, Melchizedek greets Abraham as he returns from the slaughter of the kings.
“And Melchizedek king of Salem brought forth bread and wine: and he was the priest of the most high God. And he blessed him, and said, Blessed be Abram of the most high God, possessor of heaven and earth: And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all” (Gen. 14:18-20).
We know from the New Testament that Melchizedek was a type of Jesus Christ. The Lord was to be a priest forever, after the order of Melchizedek—meaning that the Lord was going to do the same sorts of things that Melchizedek.
Note here, then, that Melchizedek brings the bread and wine to Abraham, not the other way around. Note that Abraham was blessed by Melchizedek, and he was blessed in the aftermath of his defeat of the pagan kings. He was also blessed for this in the presence of another unbelieving king, the king of Sodom, one that Abraham refused to receive any blessing from. Abraham spoiled the pagan kings, and gave a tithe of the spoils to Melchizedek. He refused to take any share of the spoils himself—in essence, he forced the king of Sodom to tithe, but did it in a way that would not permit anyone to slander his motives for doing so.
In exchange, he received a blessing, and the bread and wine. And that is exactly what you are receiving.