John Chrysostom

"Sharing with the necessity of the saints." He does not say, Bestow upon, but "share with the necessity of the saints," to show that they receive more than they give, that it is a matter of merchandise, because it is a community. Do you bring in money? They bring you in boldness toward God. "Given to hospitality." He does not say doing it, but "given" to it, so to instruct us not to wait for those that shall ask it, and see when they will come to us, but to run to them, and be given to finding them. Thus did Lot, thus Abraham. …

Homily on Romans 21 ↗

Theophylact of Ohrid

Having said above: "he who shows mercy, with cheerfulness," he opened his hand to all in general, but now he teaches about almsgiving to the faithful: for he calls them saints. And he did not say: help them in their needs, but: "share in them," showing thereby that assistance is a transaction and a common profit; for you give money, and they repay you with heaven. He also did not say: in great expenses, but: "in needs," so as to satisfy the needs of the saints. …

Commentary on Romans ↗

Cyprian

Our brotherhood, considering all these things according to your letter, and sorrowfully examining, have all promptly and willingly and liberally gathered together supplies of money for the brethren, being always indeed, according to the strength of their faith, prone to the work of God, but now even more stimulated to salutary works by the consideration of so great a suffering. …

Epistle LIX ↗

Thomas Aquinas

Then when he says, communicating to the necessities of the saints, he discusses charity with regard to certain particular persons. First, as regards the needy; second, as regards enemies, at bless those who persecute you (Rom 12:14). Concerning the first he does two things. First, he urges in general that the benefits of charity be afforded to the needy, when he says: communicating to the necessities of the saints. …

Commentary on Romans ↗