Albert Barnes Commentary Proverbs 16:26

"The appetite of the laboring man laboreth for him; For his mouth urgeth him [thereto]." — Proverbs 16:26 (ASV)

He that laboreth - literally, as in the margin, that is, “The desire of the laborer labors for him” (or, helps him in his work), “for his mouth urges him on.” Hunger of some kind is the spring of all hearty labor. Without that the man would sit down and take his ease. So also, unless there is a hunger in the soul, craving to be fed, there can be no true labor after righteousness and wisdom .