John Calvin Commentary 2 Thessalonians 3:13

"But ye, brethren, be not weary in well-doing." — 2 Thessalonians 3:13 (ASV)

And you, brethren. Ambrose believes that this is added so that the rich would not, in an ungenerous spirit, refuse to offer their help to the poor, because he had urged them to eat every one his own bread. And, undoubtedly, we see how many are inappropriately clever in seizing an excuse for inhumanity.

Chrysostom explains it this way—that idle people, however justly they may be condemned, must nevertheless be helped when in need. I simply believe that Paul intended to guard against a cause of offense, which might arise from the idleness of a few. For it usually happens that those who are otherwise particularly ready and alert to show generosity become less enthusiastic on seeing that they have wasted their kindness by misdirecting it.

Therefore, Paul urges us that, although there are many who are undeserving, while others abuse our generosity, we must not for this reason stop helping those who need our help. This is a statement worth noting—that no matter how ingratitude, sullenness, pride, arrogance, and other inappropriate attitudes on the part of the poor may tend to annoy us, or to discourage us out of weariness, we must nevertheless strive never to stop aiming to do good.