John Calvin Commentary Galatians 6:9

"And let us not be weary in well-doing: for in due season we shall reap, if we faint not." — Galatians 6:9 (ASV)

Let us not be weary in well-doing. Well-doing (καλὸν) does not simply mean doing our duty, but the performance of acts of kindness, and it relates to people. We are instructed not to be weary in assisting our neighbors, in performing good deeds, and in exercising generosity. This precept is highly necessary, for we are naturally reluctant to discharge the duties of brotherly love, and many unpleasant occurrences arise by which the ardor of even the best-intentioned people is apt to be cooled.

We meet with many unworthy and ungrateful persons. The vast number of needy situations overwhelms us, and the appeals that crowd upon us from every direction exhaust our patience. Our warmth is diminished by the coolness of other people. In short, the world presents innumerable hindrances, which tend to lead us away from the right path. Therefore, Paul most appropriately admonishes us not to relax through weariness.

If we faint not. This means we will reap the fruit God promises, if we persevere to the end (Matthew 10:22). Those who do not persevere are like lazy farmers who, after plowing and sowing, leave the work unfinished and neglect to take the necessary precautions to protect the seed from being devoured by birds, scorched by the sun, or destroyed by cold. It is useless to begin doing good if we do not press forward to the goal.

In due season. Let no one, from a desire to gather the fruit in this life, or before its proper time, deprive himself of the spiritual harvest. The desires of believers must be both supported and restrained by the exercise of hope and patience.