John Chrysostom

"And I beseech you, brethren, suffer the word of exhortation, for indeed I have written a letter unto you in few words." Seest thou that what he wrote to no one else, he writes to them? For (he means) I do not even trouble you with long discourse. And having written thus much, he said this was little, in comparison with what he was going to say. As he says also in another place, "As I wrote to you in few words: whereby when ye read, ye may understand my knowledge in the mystery of Christ." (Eph. iii. 3, 4.) And observe his wisdom. …

Homily on Hebrews 34 ↗

Theophylact of Ohrid

Do you not see? He offers them what he offered to no one else. He does not say "persuasions," but "exhortations," that is, encouragements, reassurances toward endurance, since he was addressing his words to those who had been subjected to persecution. Despite the fact that he said so much, he still says "not much," of course in comparison with what he wished to say. …

Commentary on Hebrews ↗

Oecumenius

"bear with the word of encouragement." Gladly accept the encouragement sent to you through the letters from me. Paul does not say, of counsel or exhortation, but, because of the tribulations in which they were, he speaks of encouragement, that is, of consolation, of the call to endure. "for I have written to you briefly." Briefly, as it relates to what is to be said in the future, there are indeed many things, if everything has been said.

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

Then (v. 22) he adds a petition in which he excuses himself; then he concludes the epistle. In regard to the first he does three things: first, he gives his excuse; secondly, he recommends the messenger through whom he writes (v. 23); thirdly, he sends several greetings (v. 24). …

Commentary on Hebrews ↗