William Burkitt on 1 Corinthians 9:11

A third argument for the ministers' maintenance is here taken from common justice: they sow spiritual things. That is, they dispense the word and sacraments, and endeavour to make men spiritual and holy here, and happy hereafter; and therefore they ought to reap some of their people's carnal things, things for the support of their lives, and subsistence for themselves and their families: so that the ministers of God are not indebted both to God and them; they give their people things of a much greater value, and more excellent use, for things of a much lesser value, and more inferior use; for their carnal things they give them spiritual things.