What does Hebrews 7:2 mean?

In Genesis chapter 14, Abraham returns from rescuing his war-captive nephew, Lot. Abraham is met by both the king of Sodom and a figure named Melchizedek (Genesis 14:14–24). At this meeting, Melchizedek gives Abraham a blessing along with bread and wine, and Abraham gives Melchizedek a tithe. The king of Sodom, on the other hand, gets a flat refusal from Abraham, who wants nothing to do with him, his wealth, or his people.

The point of this passage is showing that Melchizedek was a figure greater even than Abraham. This factors into later explanations of the priesthood, and how Jesus Christ fulfills that role with perfection. The writer points out that Melchizedek's name literally means king of righteousness. He also points out that the name of the city where Melchizedek rules is called Salem, which literally means peace. This makes the man whom Abraham honored the king of righteousness, the king of peace, and the priest of God Most High (Genesis 14:18). When Abraham gives this king-priest a tithe, it is not only a sign of respect, but a sign of submission. As the following verses point out, blessings naturally come from the superior to the inferior, and tithes are naturally given from the lesser to the greater.