Solomon had commended eloquence, or the sweetness of the lips (Pro 16:21), and seemed to prefer it before wisdom; but here he corrects himself, as it were, and shows that unless there be a good treasure within to support the eloquence it is worth little. Wisdom in the heart is the main matter. 1. It is this that directs us in speaking, that teaches the mouth what to speak, and when, and how, so that what is spoken may be proper, and pertinent, and seasonable; otherwise, though the language be ever so fine, it had better be unsaid. 2. It is this that gives weight to what we speak and adds learning to it, strength of reason and force of argument, without which, let a thing be ever so well worded, it will be rejected, when it comes to be considered, as trifling. Quaint expressions please the ear, and humour the fancy, but it is learning in the lips that must convince the judgment, and sway that, to which wisdom in the heart is necessary.

The heart of the wise teacheth his mouth,.... That is, a man that is wise in heart, as in Pro 16:21; his heart will teach his mouth what to say, when to say it, and before whom; it will prompt him to matter, that he shall not be at a loss what to say, nor how to say; it will furnish him with words and things; out of the abundance of the heart the mouth speaketh, Mat 12:34;

and addeth learning to his lips: so that he does not deliver out mere words, but solid learning along with them, instructive to himself and others. The Targum is,

"and by his lips he addeth doctrine;''

or increases knowledge.

The heart is the source of wisdom flowing from the mouth.