Wisdom resteth in the heart of him that hath understanding: but that which is in the midst of fools is made known. Wisdom resteth in the heart of him that hath understanding - not merely superficially in the lips, as in the case of those making a display, but in the inmost recesses of "the heart." "Resteth" implies the tranquil and modest spirit of the wise, and the permanence of their keeping of wisdom; and especially that it is the fruit of the Spirit from above descending and abiding on them (Numbers 11:25-26; Isaiah 11:2; 2 Kings 2:15. Contrast Ecclesiastes 7:9). The wise does not draw forth his wisdom from its resting-place within his heart at random, but in proper place and time, as the occasion may require.
But (that which is) in the midst (in the inmost part) of fools is made known - namely, their folly to be supplied from the contrary to "wisdom" in the parallel clause, 'Exhibits itself to be known.' Fools cannot long disguise their folly; it is sure to betray itself in unseasonable speaking at random, without choice or judgment (Proverbs 10:14; Proverbs 12:23; Proverbs 13:16). The Hebrew adage says, 'A vessel full of coins will make no noise; but if there be only one coin in it, it will make a rattle.' The more learned one is, the more modest he will be; the more unlearned, the more presumptuous and ostentatious.