John Chrysostom

"And verily they that are of the sons of Levi who receive the office of Priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham." So great (he would say) is the superiority of the priesthood, that they who from their ancestors are of the same dignity, and have the same forefather, are yet far better than the rest. At all events they "receive tithes" from them. …

Homily on Hebrews 12 ↗

Theophylact of Ohrid

Now he shows in what way Melchizedek is above Abraham, saying that the ministers from the tribe of Levi received tithes from the people (Lev. 27:30–32), evidently as better and more honorable men on account of the dignity of the priesthood. For why else does the people itself, enduring heavy labors and hardships, bring tithes of every kind to priests who do not undergo such labors and do not till the land, if not because they are more sacred and serve a higher purpose? …

Commentary on Hebrews ↗

Oecumenius

It confirms that he who was in the figure of Christ was greater than the priests of the Jews. The Levites, he says, being more honorable than the rest of the people, receive the tithes. For what is taken from brothers who have the same father? Therefore, it is evident that the tithes are a symbol of honor and of being more sacred. Thus, Melchizedek, being a foreigner and without genealogy, would not have received tithes from the patriarch unless he was greater than him. …

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

337. – Then (v. 5) he shows the pre-eminence of Melchizedek's priesthood over that of the Levitical. In regard to this he does two things: first, he states his proposition; secondly, from this he concludes his thesis, namely, that Christ's priesthood is preferred to the Levitical (v. 11). The first is divided into two parts: in the first he states his proposition; in the second he rejects a certain response (v. 9). …

Commentary on Hebrews ↗