Anger resteth in the bosom of fools - A wise man, off his guard, may feel it for a moment: but in him it cannot rest: it is a fire which he immediately casts out of his breast. But the fool - the man who is under the dominion of his own tempers, harbors and fosters it, till it takes the form of malice, and then excites him to seek full revenge on those whom he deems enemies. Hence that class of dangerous and empty fools called duellists.

Be not hasty in thy spirit to be angry,.... With men, for every word that is said, or action done, that is not agreeable; encourage not, but repress, sudden angry emotions of the mind; be not quick of resentment, and at once express anger and displeasure; but be slow to wrath, for such a man is better than the mighty, James 1:19, Proverbs 16:32; or with God, for his corrections and chastisements; so the Targum,
"in the time that correction from heaven comes upon thee, do not hasten in thy soul to be hot (or angry) to say words of rebellion (or stubbornness) against heaven;''
that advice is good,
"do nothing in anger (l);''
for anger resteth in the bosom of fools; where it riseth quick, and continues long; here it soon betrays itself, and finds easy admittance, and a resting dwelling place; it easily gets in, but it is difficult to get it out of the heart of a fool; both which are proofs of his folly, Proverbs 12:16; see Ephesians 4:26; the bosom, or breast, is commonly represented as the seat of anger by other writers (m).
(l) Isocrates ad Nicoclem, p. 36. (m) "In pectoribus ira considit", Petronius; "iram sanguinei regio sub pectore cordis", Claudian. de 4. Consul. Honor. Panegyr. v. 241.

angry--impatient at adversity befalling thee, as Job was (Ecclesiastes 5:2; Proverbs 12:16).

In this verse the author warns against this pride which, when everything does not go according to its mind, falls into passionate excitement, and thoughtlessly judges, or with a violent rude hand anticipates the end. אל־תּב: do not overturn, hasten not, rush not, as at Ecclesiastes 5:1. Why the word בּרוּחך, and not בנפשך or בלבך, is used, vid., Psychol. pp. 197-199: passionate excitements overcome a man according to the biblical representation of his spirit, Proverbs 25:28, and in the proving of the spirit that which is in the heart comes forth in the mood and disposition, Proverbs 15:13. כּעוס is an infin., like ישׁון, Ecclesiastes 5:11. The warning has its reason in this, that anger or (כעס, taken more potentially than actually) fretfulness rests in the bosom of fools, i.e., is cherished and nourished, and thus is at home, and, as it were (thought of personally, as if it were a wicked demon), feels itself at home (ינוּח, as at Proverbs 14:33). The haughty impetuous person, and one speaking out rashly, thus acts like a fool. In fact, it is folly to let oneself be impelled by contradictions to anger, which disturbs the brightness of the soul, takes away the considerateness of judgment, and undermines the health, instead of maintaining oneself with equanimity, i.e., without stormy excitement, and losing the equilibrium of the soul under every opposition to our wish.
From this point the proverb loses the form "better than," but tov still remains the catchword of the following proverbs. The proverb here first following is so far cogn., as it is directed against a particular kind of ka'as (anger), viz., discontentment with the present.