A soft answer - Gentleness will often disarm the most furious, where positive derangement has not taken place; one angry word will always beget another, for the disposition of one spirit always begets its own likeness in another: thus kindness produces kindness, and rage produces rage. Universal experience confirms this proverb.

A soft answer turneth away wrath,.... Mild words, gentle expressions, delivered with kindness and tenderness, humility and submission; these will work upon a man's passions, weaken his resentments, and break and scatter the storm of wrath raised in his breast, just breaking forth in a very boisterous and blustering manner; so high winds are sometimes laid by soft showers. Thus the Ephraimites were pacified by Gideon's mild answer; and David by Abigail's very submissive and respectful address, Judges 8:1;
but grievous words stir up anger; such as are rough and menacing, scornful and sneering, reproachful and reviling, proud, haughty, and overbearing; like those of Jephthah to the Ephraimites; and of the Ephraimites to the Gileadites; and of Nabal to David's servants, concerning him; and of Rehoboam, who answered the people roughly: in all which instances anger was stirred up, and either were or like to have been attended with bad consequences, Judges 12:1. Or a "word" causing, or rather expressing, "grief" (r); upbraiding others with being the cause of grief to them.
(r) "verbum vel sermo doloris", Montanus, Vatablus, Michaelis; vid. Gussetius, p. 177.

A right cause will be better pleaded with meekness than with passion. Nothing stirs up anger like grievous words.

(Proverbs. 15:1-33)
soft--tender or gentle.
turneth . . . wrath--from any one.
stir up--as a smouldering fire is excited.

We take these verses together as forming a group which begins with a proverb regarding the good and evil which flows from the tongue, and closes with a proverb regarding the treasure in which blessing is found, and that in which no blessing is found.

1 A soft answer turneth away wrath,
And a bitter word stirreth up anger.
In the second line, the common word for anger (אף, from the breathing with the nostrils, Proverbs 14:17) is purposely placed, but in the first, that which denotes anger in the highest degree (חמה from יחם, cogn. חמם, Arab. hamiya, to glow, like שׁנה from ישׁן): a mild, gentle word turns away the heat of anger (excandescentiam), puts it back, cf. Proverbs 25:15. The Dagesh in רּך follows the rule of the דחיק, i.e., of the close connection of a word terminating with the accented eh, aah, ah with the following word (Michlol 63b). The same is the meaning of the Latin proverb:
Frangitur ira gravis
Quando est responsio suavis.
The דבר־עצב produces the contrary effect. This expression does not mean an angry word (Ewald), for עצב is not to be compared with the Arab. ghaḍab, anger (Umbreit), but with Arab. 'aḍb, cutting, wounding, paining (Hitzig), so that דבר מעציב is meant in the sense of Psalm 78:40 : a word which causes pain (lxx λυπηρός, Theod. πονικός), not after the meaning, a word provoking to anger (Gesenius), but certainly after its effect, for a wounding word "makes anger arise." As one says of anger שׁב, "it turns itself" (e.g., Isaiah 9:11), so, on the other hand, עלה, "it rises up," Ecclesiastes 10:4. The lxx has a third line, ὀργὴ ἀπόλλυσι καὶ φρονίμους, which the Syr. forms into a distich by the repetition of Proverbs 14:32, the untenableness of which is at once seen.