Proverbs 18:20

Note, 1. Our comfort depends very much upon the testimony of our own consciences, for us or against us. The belly is here put for the conscience, as Pro 20:27. Now it is of great consequence to us whether that be satisfied, and what that is filled with, for, accordingly, will our satisfaction be and our inward peace. 2. The testimony of our consciences will be for us, or against us, according as we have or have not governed our tongues well. According as the fruit of the mouth is good or bad, unto iniquity or unto righteousness, so the character of the man is, and consequently the testimony of his conscience concerning him. "We ought to take as great care about the words we speak as we do about the fruit of our trees or the increase of the earth, which we are to eat; for, according as they are wholesome or unwholesome, so will the pleasure or the pain be wherewith we shall be filled." So bishop Patrick.

— Matthew Henry's Concise Commentary (public domain)

(Compare Pro 12:14; Pro 13:2). Men's words are the fruit, or, increase of his lips, and when good, benefit them. satisfied with--(Compare Pro 1:31; Pro 14:14).

— Jamieson-Fausset-Brown Commentary (public domain)