John Chrysostom

And having spoken concerning the Son, both what related to the Economy, and what related to the Creation, and to His sovereignty, and having shown His co-equal dignity, and that as absolute Master He ruleth not men only but also the powers above, he next exhorts them, having made out his argument, that we ought to give heed to the things which have been heard. "Wherefore we ought to give more earnest heed" (saith he) "to the things which we have heard." Why "more earnest"? …

Homily on Hebrews 3 ↗

Theophylact of Ohrid

Since, he says, so great is the superiority of the Son who spoke to us over the prophets and angels, the ministers of the Old Testament, what He said must be heeded more than the law. But he did not say this directly, so as not to shock them at the beginning; he left it to them to draw this conclusion from what follows. He says this not comparing the Old Testament with the New — no, but against the opinion of those who speak with great glory of the Old Testament and neglect the New. …

Commentary on Hebrews ↗

Oecumenius

Because, he says, the one who has spoken to us, the Son, is so much greater than the prophets and the angels who served in the Old Testament, we must pay closer attention to what has been spoken by him, rather than as we were inclined to the law. "Lest at any time we drift away." This is, let us not fall away from what is honorable and from the way that leads to salvation.

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

89. – After showing in a number of ways Christ's superiority over the angels, the Apostle here concludes that Christ's doctrine, namely, the New Testament, deserves more obedience than the Old Testament. In regard to this he does three things: first, he states the conclusion intended; secondly, he supports this conclusion with a reason (v. 2); thirdly, he confirms the consequence (v. 5). 90. – In regard to the first it should be noted that after giving the judicial and moral precepts of the Law in Ex. (chap. …

Commentary on Hebrews ↗