John Chrysostom

"And let us consider one another to provoke unto love and to good works." He knew that this also arises from "gathering together." For as "iron sharpeneth iron," so also association increases love. For if a stone rubbed against a stone sends forth fire, how much more soul mingled with soul! But not unto emulation (he says) but "unto the sharpening of love." What is "unto the sharpening of love"? Unto the loving and being loved more. "And of good works"; that so they might acquire zeal. …

Homily on Hebrews 19 ↗

Theophylact of Ohrid

He points to the perfection of love. For, he says, "let us consider one another," that is, let us look to see if there is someone virtuous, so as to imitate such a person, not in order to envy, but to find for ourselves greater encouragement to perform the very same good deeds that he has. This encouragement is a matter of love, not of envy. For, as iron sharpens iron, so also a soul, associating with another soul, stirs it up to the same thing, yet in love. …

Commentary on Hebrews ↗

Oecumenius

"to provoke unto love." To stir up and increase love for one another. "and good works." And to provoke each other to zeal in good works. "not forsaking the assembling of ourselves together." For to always come together in the same place is a source of love. Therefore, it prohibits separation. For the work of love is not division, but the exact union. He called the assembly the harmony.

The Pseudo-Oecumenian Catena on Hebrews ↗

Thomas Aquinas

510. – Then (v. 24) he mentions what pertains to charity. He does three things: first, he does what he said; secondly, he removes the contrary of charity (v. 25); thirdly, he assigns the reason from the fittingness of the time (v. 25b). 511. – In regard to the first it should be noted that although charity principally clings to God, it is shown by love of neighbor: 'He that does not love his neighbor, whom he sees, how can he love God whom he does not see?' (1 Jn. 4:20). …

Commentary on Hebrews ↗