Proverbs 13:3

3 He that guardeth his mouth keepeth his soul; He that openeth his lips, to him it is destruction. 3a is extended in Pro 21:23 to a distich. Mouth and soul stand in closest interchangeable relation, for speech is the most immediate and continuous expression of the soul; thus whoever guards his mouth keeps his soul (the Venet., with excellent rendering of the synonym, ὁ τηρῶν τὸ στόμα ἑαυτοῦ φυλάσσει τὴν ψυχὴν ἑαυτοῦ), for he watches that no sinful vain thoughts rise up in his soul and come forth in words, and because he thus keeps his soul, i.e., himself, safe from the destructive consequences of the sins of the tongue. On the contrary, he who opens wide his lips, i.e., cannot hold his mouth (lxx ὁ δὲ προπετὴς χείλεσιν), but expresses unexamined and unconsidered whatever comes into his mind and gives delight, he is destruction to himself (supply הוּא), or to him it is destruction (supply זאת); both interpretations are possible, the parallelism brings nearer the former, and the parallel Pro 18:7 brings nearer the latter. פּשׂק means to spread (Schultens diducere cum ruptura vel ad rupturam usque), here the lips, Pih. Eze 16:25, the legs, Arab. fashkh, farshkh; vid., regarding the R. פש, to extend, to spread out, Fleischer in the supplements to the A. L. Z. 1843, col. 116. Regarding the Mishle word מחתּה, vid., under Pro 10:14.

Note, 1. A guard upon the lips is a guard to the soul. He that is cautious, that thinks twice before he speaks once, that, if he have thought evil, lays his hand upon his mouth to suppress it, that keeps a strong bridle on his tongue and a strict hand on that bridle, he keeps his soul from a great deal both of guilt and grief and saves himself the trouble of many bitter reflections on himself and reflections of others upon him. 2. There is many a one ruined by an ungoverned tongue: He that opens widely his lips, to let our quod in buccam venerit - whatever comes uppermost, that loves to bawl, and bluster, and make a noise, and affects such a liberty of speech as bids defiance both to God and man, he shall have destruction. it will be the destruction of his reputation, his interest, his comfort, and his soul for ever, Jam 3:6.

13:3 Having control of the tongue demonstrates wisdom (see Jas 3:1-12).