Solomon
Proverbs 16:23ESV·traditional attribution
The heart of the wise makes his speech judicious and adds persuasiveness to his lips.
Matthew Henry Presbyterian
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.
John Gill Reformed Baptist
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...
Jamieson-Fausset-Brown Reformed
The heart is the source of wisdom flowing from the mouth.