3 For to their power, I bear record, yea, and beyond their power they were willing of themselves;
[AD 384] Ambrosiaster on 2 Corinthians 8:3
Because they gave themselves to God wholeheartedly, they wanted to offer even more than their strength allowed.

[AD 407] John Chrysostom on 2 Corinthians 8:3
The greatness of the Macedonians can be seen from the fact that they gave voluntarily, in spite of their poverty.

[AD 407] John Chrysostom on 2 Corinthians 8:3
"For according to their power, I bear witness." Trustworthy is the witness. "And beyond their power." That is, it "abounded unto the riches of their liberality." Or rather, he makes this plain, not by this expression alone, but also by all that follows; for he says, "of their own accord." Lo! Yet another excessiveness.