Hebrews 7:2-5

and Abraham gave him a tenth of everything. First, the name Melchizedek means “king of righteousness”; then also, “king of Salem” means “king of peace.” Without father or mother, without genealogy, without beginning of days or end of life, resembling the Son of God, he remains a priest forever. Just think how great he was: Even the patriarch Abraham gave him a tenth of the plunder! Now the law requires the descendants of Levi who become priests to collect a tenth from the people—that is, from their fellow Israelites—even though they also are descended from Abraham.