John Calvin Commentary Galatians 6:10

"So then, as we have opportunity, let us work that which is good toward all men, and especially toward them that are of the household of the faith." — Galatians 6:10 (ASV)

While we have opportunity. The metaphor is still pursued. Not every season is suitable for tilling and sowing. Active and prudent farmers will observe the proper season and will not lazily allow it to pass unimproved. Therefore, since God has set apart the whole of the present life for plowing and sowing, let us make use of this season, lest, through our negligence, it be taken from us.

Beginning with generosity to ministers of the gospel, Paul now makes a wider application of his doctrine, exhorting us to do good to all men, but recommending to our particular regard the household of faith, or believers, because they belong to the same family as ourselves. This analogy is intended to inspire us to the kind of fellowship that ought to be maintained among the members of one family. There are duties we owe to all people arising from our common nature; but the tie of a more sacred relationship, established by God himself, binds us to believers.