Albert Barnes Commentary 1 Corinthians 9:10

"or saith he it assuredly for our sake? Yea, for our sake it was written: because he that ploweth ought to plow in hope, and he that thresheth, [to thresh] in hope of partaking." — 1 Corinthians 9:10 (ASV)

Or does he say it altogether for our sakes? The word "altogether"—pantwv—cannot mean that this was the sole and only design of the law, to teach that ministers of the gospel were entitled to support; for,

1. this would be directly contrary to the law itself, which had some direct and undoubted reference to oxen;
2. the scope of the argument here does not require this interpretation, since the whole object will be met by supposing that this settled a principle of humanity and equity in the Divine law, according to which it was proper that ministers should have a support; and,
3. the word "altogether"—pantwv—does not of necessity require this interpretation. It may be rendered chiefly, mainly, principally, or doubtless. Luke 4:23, You will surely (pantwv, certainly, surely, doubtless) say to me this proverb, etc. Acts 18:21, I must by all means (pantwv, certainly, surely) keep this feast.Acts 21:22, The multitude must needs (pantwv, will certainly, surely, inevitably) come together, etc. Acts 28:4, No doubt (pantwv) this man is a murderer, etc.

The word here therefore means, that the principle stated in the law about the oxen was so broad and humane, that it might certainly, surely, particularly be regarded as applicable to the case under consideration. An important and material argument might be drawn from it; an argument from the less to the greater. The precept enjoined justice, equity, humanity; and that was more applicable to the case of the ministers of the gospel than to the case of oxen.

For our sakes, etc. To show that the laws and requirements of God are humane, kind, and equitable; not that Moses had Paul or any other minister in mind, but the principle was one that applied particularly to this case.

That he who plows, etc. The Greek in this place would be more literally and more properly rendered, "For (oti) he who plows OUGHT (ofeilei) to plow in hope;" that is, in hope of reaping a harvest, or of obtaining success in his labours.

And the sense is, "The man who cultivates the earth, in order that he may be excited to industry and diligence, ought to have a reasonable prospect that he shall himself be permitted to enjoy the fruit of his labours. This is the case with those who do plow. And if this should be the case with those who cultivate the earth, it is as certainly reasonable that those who labour in God's husbandry, and who devote their strength to his service, should be encouraged with a reasonable prospect of success and support."

And that he who threshes, etc. This sentence, in the Greek, is very elliptical and obscure; but the sense is, evidently, "He who threshes ought to partake of his hope; that is, of the fruits of his hope, or of the result of his labour. It is fair and right that he should enjoy the fruits of his toil. So in God's husbandry; it is right and proper that they who toil for the advancement of his cause should be supported and rewarded."

The same sentiment is expressed in 2 Timothy 2:6: The husbandman that laboureth must be first partaker of the fruits.