2 Corinthians 8:3

3.To their power, and even beyond their power. When he says that they were willing of themselves, he means that they were, of their own accord, so well prepared for the duty, that they needed no exhortation. It was a great thing — to strive up to the measure of their ability; and hence, to exert themselves beyond their ability, showed a rare, and truly admirable excellence. (663) Now he speaks according to the common custom of men, for the common rule of doing good is that which Solomon prescribes, (Proverbs 5:15) —

to drink water out of our own fountains, and let the rivulets go past, that they may flow onwards to others. (664)

The Macedonians, on the other hand, making no account of themselves, and almost losing sight of themselves, concerned themselves rather as to providing for others. (665) In fine, those that are in straitened circumstances are willing beyond their ability, if they lay out any thing upon others from their slender means.