The lips of the wise disperse knowledge (Proverbs 15:2; Proverbs 10:31). The LXX. takes the verb יִרָוּ in its other signification of "binding" or "embracing," and translates, "The lips of the wise are bound ( δέδεται) with knowledge;" i.
e. knowledge is always on them and controls their movements. The wise know when to speak, when to be silent, and what to say. But the heart of the foolish doeth not so; i.e. doth not disperse knowledge.
Vulgate, cor stultorum dissimile erit, "will be unlike," which probably means the same as the Authorized Version. (Compare a similar use of the words lo-ken in Genesis 48:18; Exodus 10:11.) But the contrast is stated rather weakly by this rendering, lips and heart having the same office to perform; hence it is better, with Delitzsch, Ewald, and others, to take כֵן (ken) as an adjective in the sense of "right" or "trustworthy," and either to supply the former verb, "disperseth that which is not right," or to render, "The heart of the foot is not directed right;" the fool goes astray, and leads himself and others into error.
Septuagint, "The hearts of fools are not safe ( ἀσφαλεῖς)."