Another aspect of the truth of Proverbs 10:14.

A prudent man concealeth knowledge - "If a fool hold his peace he may pass for a wise man." I have known men of some learning, so intent on immediately informing a company how well cultivated their minds were, that they have passed either for insignificant pedants or stupid asses.

A prudent man concealeth knowledge,.... Of things natural or divine, which he is furnished with; not but that he is willing to communicate it, as he should, at proper times, in proper places, and to proper persons; but he does not needlessly and unseasonably speak of it; he does not make a show of it, or boast and brag of it: he modestly forbears to speak of what he knows, but when there is a necessity for it, even of that which may be lawfully divulged; which is a point of prudence and modesty; otherwise it is criminal to reveal secrets, or publish what should be kept private or should not be known. Aben Ezra interprets it of a wise man's hiding his knowledge in his heart, that he may not forget it;
but the heart of fools proclaimeth foolishness; that which they have in their hearts and minds, and which they take for deep knowledge, profound and recondite learning, they proclaim with their mouths in a noisy and clamorous way; and while they declare their ill shaped notions, their incoherent and unconnected ideas of things, they betray their ignorance and folly, as ostentatious men do.

Foolish men proclaim to all the folly and emptiness of their minds.

concealeth--by his modesty (Proverbs 10:14; Proverbs 11:13).
heart . . . proclaimeth--as his lips speak his thoughts (compare Ecclesiastes 10:3).

23 A prudent man conceals knowledge,
And a heart-fool proclaims imbecility.
In 23a Proverbs 12:16 is repeated, only a little changed; also 16a corresponds with 23a, for, as is there said, the fool knows not how to keep his anger to himself, as here, that a heart-fool (cf. the lying mouth, 22a) proclaims (trumpets forth), or as Proverbs 13:16 says, displays folly without referring to himself the si tacuisses. To this forward charlatan blustering, which intends to preach wisdom and yet proclaims in the world mere folly, i.e., nonsense and imbecility, and thereby makes itself troublesome, and only to be laughed at and despised, stands in contrast the relation of the אדם ערוּם, homo callidus, who possesses knowledge, but keeps it to himself without bringing it forth till an occasion presents itself for setting it forth at the right place, at the right time, and to the right man. The right motive also regulates such silence as well as modesty. But this proverb places it under the point of view of prudence.

Concealeth - He does not unseasonably utter what he knows. Foolishness - Betrays his ignorance and folly.