John Gill's Exposition of the Whole Bible
Proverbs 15:7
The lips of the wise disperse knowledge,.... Scatter it about for the benefit of others; they are communicative and diffusive of it unto others, that fruit may abound to their account: so the first ministers of the Gospel diffused the savour of the knowledge of Christ and his Gospel in every place; their words went into all the earth, and their sound to the end of the world; and so every Gospel minister will speak according to the oracles of God, and according to the abilities and measure of the gift which he has received; and to the utmost of his power feeds souls with knowledge and understanding;
but the heart of the foolish [doth] not so; does not disperse knowledge, for he has no solid substantial knowledge in him: or, "the heart of the foolish [is] not right" x; it is full of folly and wickedness: or "the heart of the foolish [does] not [disperse that which is] right" y; true and right things, and the knowledge of them; but, on the contrary, as in Proverbs 15:2, "pours out foolishness".
x לא כן "non erit rectum", Pagninus, Baynus; "non est rectum", Piscator, Mercerus. y "Spargit quod abest a recto", Junius Tremellius, Amama "eventilant non rectum", Schultens, Cocceius.