Prov 16:21

“The wise-hearted shall be called understanding He who learned wisdom from his teacher. shall be called understanding. Ultimately, he will be understanding in matters and keen in his wisdom, and they will call him understanding. and the sweetness of speech increases learning When a person explains his words to a pupil and makes his words sweet with reasons, he increases learning.”

“Note, 1. Those that have solid wisdom will have the credit of it; it will gain them reputation, and they shall be called prudent grave men, and a deference will be paid to their judgment. Do that which is wise and good and thou shalt have the praise of the same. 2. Those that with their wisdom have a happy elocution, that deliver their sentiments easily and with a good grace, are communicative of their wisdom and have words at will, and good language as well as good sense, increase learning; they diffuse and propagate knowledge to others, and do good work with it, and by that means increase their own stock. They add doctrine, improve sciences, and do service to the commonwealth of learning. To him that has, and uses what he has, more shall be given.”

“The wise in heart shall be called prudent,.... He that has true wisdom in the inward part; who knows his heart and the haughtiness of it; who has the fear of God in it, which is the beginning of wisdom; who is wise unto salvation, not only knows the scheme of it, but is experimentally acquainted with it; who has not head knowledge and wisdom only, but heart knowledge and wisdom, and behaves wisely in his life and conversation; who is so wise and endued with knowledge, as, out of a good conversation, to show his works with meekness of wisdom; such a man is called, reckoned, accounted, and spoken well of, as a prudent man among all wise and knowing persons; and the sweetness of the lips increaseth learning; who, besides a wise heart and a knowing head, have the gift of elocution; can deliver themselves in a flowing easy style; can clothe their thoughts with proper words, and convey their ideas in clear expressions, in a very edifying and instructive manner: these communicate knowledge to others, and increase it in themselves: for, while they are improving others, they improve themselves and learning also, whether it be divine or human; these are such who are "apt to teach", Ti1 3:2; and if they have proper hearers to attend them, they will "increase in learning", as a just man does, Pro 9:9.”

“Four proverbs of wisdom with eloquence: 21 The wise in heart is called prudent, And grace of the lips increaseth learning. Elsewhere (Pro 1:5; Pro 9:9) הוסיף לקח means more than to gain learning, i.e., erudition in the ethico-practical sense, for sweetness of the lips (dulcedo orationis of Cicero) is, as to learning, without significance, but of so much the greater value for reaching; for grace of expression, and of exposition, particularly if it be not merely rhetorical, but, according to the saying pectus disertos facit, coming out of the heart, is full of mind, it imparts force to the instruction, and makes it acceptable. Whoever is wise of heart, i.e., of mind or spirit (לב = the N.T. νοῦς or πνεῦμα), is called, and is truly, נבון [learned, intelligent] (Fleischer compares to this the expression frequent in Isaiah, "to be named" = to be and appear to be, the Arab. du'ay lah); but there is a gift which highly increases the worth of this understanding or intelligence, for it makes it fruitful of good to others, and that is grace of the lips. On the lips (Pro 10:13) of the intelligent wisdom is found; but the form also, and the whole manner and way in which he gives expression to this wisdom, is pleasing, proceeding from a deep and tender feeling for the suitable and the beneficial, and thus he produces effects so much the more surely, and beneficently, and richly.”