John Chrysostom

And first from the name. "First" (he says) "being by interpretation King of righteousness": for Sedec means "righteousness"; and Melchi, "King": Melchisedec, "King of righteousness." Seest thou his exactness even in the names? But who is "King of righteousness," save our Lord Jesus Christ? "King of righteousness. And after that also King of Salem," from his city, "that is, King of Peace," which again is characteristic of Christ. …

Homily on Hebrews 12 ↗

Theophylact of Ohrid

Here he shows in what sense Melchizedek is a prototype of Christ. And first of all, he says, learn the true meaning from the name itself. Namely: "Melchi" means king; "Sedek" means righteousness. Who else is the king of righteousness, if not our Lord Jesus Christ? And from the name of the city, he says, this is clear. For Salem, by interpretation, means "peace." But who else is the king of peace, if not Christ, who reconciled the heavenly and the earthly? The title "king of righteousness and peace" befits no man, but Christ alone.

Commentary on Hebrews ↗

Oecumenius

"gave a tenth." That is, to Melchizedek, Abraham gave a tenth, he says. "first being interpreted." Therefore, he wants to show how Melchizedek is a type of Christ, and first he does this from the name. For, he says, his name is interpreted, king of righteousness; Melchizedek, king; Salem, peace. Of whom else could he be a type, except of Christ the true King of Righteousness? Then he also mentions the other interpretation from the city. Salem is peace. …

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

330. – But it seems from Numbers (18:21) that the giving of tithes dated from the Law; therefore, there was none before the Law. I answer that the ceremonial precepts of the Old Testament are amplifications of the precepts of the natural law and of the moral precepts; therefore, in regard to what they had from the natural law, they were observed before the Law without any precept. …

Commentary on Hebrews ↗