וְהָסֵ֥ר כַּ֙עַס֙ מִלִּבֶּ֔ךָ וְהַעֲבֵ֥ר רָעָ֖ה מִבְּשָׂרֶ֑ךָ כִּֽי־הַיַּלְד֥וּת וְהַֽשַּׁחֲר֖וּת הָֽבֶל׃
Perciò rimuovi la vessazione dal tuo cuore e metti via il male dalla tua carne; Per l'infanzia e la gioventù sono vanità.
Iggeret HaRamban
Accustom yourself to always speak all of your words calmly, to every man and at every time. In doing so you will prevent your anger from flaring, which is a bad attribute in a man which may cause him to sin. And accordingly said our Rabbis, may their memories be a blessing: (Nedarim 22a) "Anyone who gets angry - all of Gehinnom holds sway over him, as it says: (Kohelet 11:10) 'And remove the anger from your heart, and take away the bad from your flesh', and 'bad' can only mean Gehinnom, as it says (Proverbs 16:4): 'And the sinner, he too, will have his day of bad'."
Orchot Tzadikim
Anger is a bad quality and just as scurvy is a disease of the body so is anger a disease of the soul. And our sages have said : "He who loses his temper is exposed to all the torments of hell" (Nedarim 22a) as it is said : "Therefore, remove vexation from thy heart, and put away evil from thy flesh" (Eccl. 11:10), and by "evil" they mean Gehenna, as it is said : "The Lord hath made everything for His own purpose, Yes, even the wicked for the day of evil" (Prov. 16:4). And not only this but an angry man is afflicted with piles as it is said : "The Lord will give you there an anguished heart and eyes that pine, and a despondent spirit" (Deut. 28:65). What ill is it that dims the eyes and pains the soul— Surely you will say "Piles".