Melchizedek didn’t trace his family line from Levi, but he still collected a tenth from Abraham. Melchizedek blessed the one who had received the promises.
This Melchizedek was the king of Salem and a priest of God Most High. When Abraham was coming back from winning a battle against a group of kings, Melchizedek met him and blessed him.
Abraham gave him a tenth of everything he’d captured in the battle. First, the name Melchizedek means “king of what is right.” Then, “king of Salem” means “king of peace.”