John Chrysostom

And yet Christ praised the contrary conduct in the widow's case, that she emptied out all of her living and gave out of her want. But because he was discoursing to Corinthians amongst whom he chose to suffer hunger; "for it were good for me rather to die, than that any man should make my glorying void;" he therefore uses a tempered exhortation, praising indeed those who had done beyond their power, but not compelling these to do so; not because he did not desire it, but because they were somewhat weak. …

Homily 17 on 2 Corinthians ↗

Theophylact of Ohrid

You, he says, are not obligated to give beyond your means so that others may live in luxury and pleasure while you suffer want and sorrow from it. The Lord praised the widow who gave all that she had (Mk. 12:44). But Paul does not do this now, partly because the Corinthians were still weak, and partly because they were wealthy, so that if they gave even according to their means, a large, considerable, and rich offering would be assembled. …

Commentary on 2 Corinthians ↗

Thomas Aquinas

Then when he says, "I do not mean," he removes a suspicion. For someone could say: if we give alms to the saints in Jerusalem, they will live in idleness, while we suffer a loss and become wretched. Therefore the Apostle first removes the suspicion; secondly he shows his intention; thirdly, he confirms it by authority. …

Commentary on 2 Corinthians ↗