גּ֖וֹי עַ֣ז פָּנִ֑ים אֲשֶׁ֨ר לֹא־יִשָּׂ֤א פָנִים֙ לְזָקֵ֔ן וְנַ֖עַר לֹ֥א יָחֹֽן׃
אַ פֿאָלק מיט אַ פֿאַרשײַטן פּנים, װאָס װעט ניט שױנען דעם פּנים פֿון אַ זקן, און אַ יונגן װעט ער ניט לײַטזעליקן.
The Improvement of the Moral Qualities
I DO not find this quality among righteous or superior men. But it is (to be found) in him whose nature resembles that of a lion, for he is one who is never sated. These are the ones of whom it is said (Deut. xxviii. 50), "A nation of fierce countenance." Upon my soul, this is a wholly detestable quality, whether (its measure be) great or small. It comes into being when the spirit of wrath prevails over a man. This quality is exercised for the purpose of wreaking vengeance upon enemies. There is no harm in making use of it in this manner, although the intelligent man ought not endeavor to be avenged upon his enemies. For this is not befitting. Thus saith the sage (Prov. xxiv. 17), "Rejoice not when thy enemy falleth." To make use of it in order that one may do evil to his fellow-man, to kill him, or to lay hold of the possessions of one who has given no offence, is reprehensible. From such as these may God preserve me, for of their ilk, the Saint said (Ps. cxxiv., i and 3), "If it had not been the Lord who was on our side, now may Israel say:" … "Then they had swallowed us up quick, when their wrath was kindled against us." A proof that this quality is only found in the wicked is the expression (Prov. xii. 10), "But the tender mercies of the wicked are cruel." Plato, the author of the laws in regard to vengeance, said, "He who desires to be revenged upon his enemies should add (a degree of) excellence to himself."
Orchot Tzadikim
Cruelty is the opposite of Mercy as it is written: "They are cruel and have no compassion" (Jer. 50:42). And this trait of cruelty is not found in righteous people but in the souls of the wicked as it is written: "The tender mercies of the wicked are cruel" (Prov. 12:10). This quality is also found in the impudent as it is written: "An impudent nation that shall have no regard for the person of the old and show no mercy to the young" (Deut. 28:50). And you already know the evil of the trait of impudence. Go forth and learn the evil nature and the punishment of cruelty, for in the matter of the reward of a wicked man — rebellious and disobedient — it is said: "A rebellious man seeks only evil, therefore, a cruel messenger shall be sent against him" (Prov. 12:11). Every cruel person has no quality of kindness in his make up, even towards himself, as it is written: "The merciful man does kindness to his own soul, but he that is cruel troubles his own flesh" (Ibid. 11:17).
The Improvement of the Moral Qualities
Sometimes satisfaction and cheerfulness follow upon hearing: thus it is said (Lev. x. 20), "When Moses heard that he was content," just as anger ensues in the absence of assent and hearkening, as (Ex. xvi. 20), "Notwithstanding, they hearkened not unto Moses." ..."And Moses was wroth with them." Hatred also results from hearing, as thou must know from the case of Esau, of whom it is said (Gen. xxvii. 34), "When Esau heard," and then follows (id. xxvii. 41), "Esau hated Jacob." Mercy is known to result from "hearing"; thus God said (Ex. xxii. 26), "I will hear, for I am merciful." It is said of the righteous dead (Prov. i. 33), "Whoso hearkeneth unto me shall dwell safely." In contrast to this, it is said of the unrighteous (Job xv. 21), "A sound of fright is in his ears: in peace the despoiler shall come upon him," and so forth. Hard-heartedness results from the want of assent; thus it is said of Pharaoh in many places (Ex. ix. 12), "The Lord hardened the heart of Pharaoh and he hearkened not." A hard-hearted people is called (Deut. xxviii. 49), "A nation whose tongue thou shalt not understand, neither shalt thou hearken unto what it speaketh," and so forth.