Adam Clarke on 1 Corinthians 9:14

Even so hath the Lord ordained - This is evidently a reference to our Lord's ordination, Mat 10:10 : The workman is worthy of his meat. And Luk 10:7 : For the laborer is worthy of his hire. And in both places it is the preacher of the Gospel of whom he is speaking. It was a maxim among the Jews, "that the inhabitants of a town where a wise man had made his abode should support him, because he had forsaken the world and its pleasures to study those things by which he might please God and be useful to men." See an ordinance to this effect in the tract Shabbath, fol. 114.