Note, 1. A good heart by the tongue becomes very useful. He that has knowledge is not only to enjoy it, for his own entertainment, but to use it, to use it aright, for the edification of others; and it is the tongue that must make use of it in pious profitable discourse, in giving suitable and seasonable instructions, counsels, and comforts, with all possible expressions of humility and love, and then knowledge is used aright; and to him that has, and thus uses what he has, more shall be given. 2. A wicked heart by the tongue becomes very hurtful; for the mouth of fools belches out foolishness, which is very offensive; and the corrupt communication which proceeds from an evil treasure within (the filthiness, and foolish talking, and jesting) corrupts the good manners of some and debauches them, and grieves the good hearts of others and disturbs them.

The tongue of the wise useth knowledge aright,.... As the heart of a wise and good man is filled with useful knowledge, civil, moral, spiritual, and evangelical; so he takes care to communicate it, at proper times and seasons, in proper places, and to proper persons; adapting it to their case and circumstances, so as it may be for their comfort, edification, and instruction, and minister grace unto them; which is using knowledge "well", as the word (s) signifies: such an use of it recommends it, and makes it appear beautiful and lovely, decorates and adorns it. Thus every good man, out of the good treasure of knowledge in his heart, brings forth his good things seasonably, to the use of edifying; in like manner, ministers of the word, scribes well instructed in the things of God, bring forth both new and old, to the profit of those to whom they minister; so Christ, as man and Mediator, had the tongue of the learned, to speak a word in season to weary souls;

but the mouth of fools poureth out foolishness; their knowledge, as they take it to be, but it is no other than folly; this they throw out in great plenty, in a hurry, without fear or wit; they "babble" it out, as the word (t) signifies, as water out of a fountain; their hearts are full of it, and their mouths proclaim it, Pro 12:23.

(s) "utitur bene", Castalio; "pulchre", Vatablus. (t) "effutit, ebullit, fundit", Vatablus; "eructat", Junius & Tremellius, Piscator; "ebullit", V. L. Tigurine version, Schultens; "scaturire facit", Michaelis.

useth . . . aright--commends knowledge by its proper use.

poureth out--utters abundantly (Pro 12:23), and so disgusts others.