Proverbs 15:7 - Joseph Benson’s Commentary on the Old and New Testaments

The lips of the wise disperse knowledge Freely communicate to others what they know, as they have opportunity; but the heart of the foolish doth not so Either because he hath no knowledge to disperse, or because he hath not a heart to perform his duty, or to do good to others. Or, as others render the word כן, and as it is rendered Genesis 42:34, is not right; that is, the heart of the foolish is not right, or disperseth (by his lips) that which is not right, namely, foolish and corrupt discourse, which is fitly opposed to knowledge.