“Rabbi Naḥman son of Rabbi Ḥisda expounded: What is meant by, Then YHWH God יִּיצֶר (yiytser), fashioned, the human (Genesis 2:7)—written with two י (yods), to show that God created two impulses, one good and the other evil. Rabbi Naḥman son of Yitsḥak demurred. According to this, he said, animals, of which it is not written יִּיצֶר (yiytser), fashioned [with two י (yods), see Genesis 2:19: and YHWH God יִּצֶר (yitser), fashioned, from the soil each beast of the field…], should have no evil impulse, yet we see that they injure and bite and kick? In truth it is as stated by Rabbi Shim’on son of Pazzi; for Rabbi Shim’on son of Pazzi said: Woe is me because of יוֹצֵרִי (Yotseri), my Maker, woe is me because of יִצֶרִי (yitseri), my urge! Or again as explained by Rabbi Yirmiyahu son of El’azar; for Rabbi Yirmiyahu son of El’azar said: God created דוּ פַּרְצוּפִין (du partsufin), two faces, in the first man, as it says, From behind and in front You shaped me (Psalms 139:5)…
Rav said: The evil impulse resembles a fly and dwells between the two openings of the heart [cf. BT Sukkah 52b], as it says, A dead fly makes the perfumer’s oil chalice stink (Ecclesiastes 10:1). Shemu’el said: It is like a kind of חִטָה (ḥittah), wheat, as it says, At the tent flap חַטָּאת (ḥattat), sin, crouches (Genesis 4:7). Our Rabbis taught: Man has two kidneys, one of which prompts him to good, the other to evil; and it is natural to suppose that the good one is on his right side and the bad one on his left, as it is written, A wise man’s mind [lit., heart] is at his right, and the fool’s mind at his left (Ecclesiastes 10:2)” (BT Berakhot 61a).
“Here is a mystery. In all actions performed by the blessed Holy One, He begins with the external, and then the kernel within… The Other Side always precedes: growing, developing, protecting the fruit. Once it has grown, it is cast aside; What the wicked will prepare, the righteous will wear (Job 27:17)—that קְלִפָּה (qelipah), shell, is thrown away and the Righteous One of the world is blessed” (Zohar 2:108b).
“Rabbi Ḥiyya opened, ‘Many are the afflictions of the righteous, but YHWH delivers him from them all (Psalms 34:20). Come and see how intensely a person is attacked, from the day that the blessed Holy One endows him with a soul to exist in this world! For as soon as a human emerges into the atmosphere, יֵצֶר הָרָע (yetser ha-ra), the evil impulse, lies ready to conspire with him, as has been said; for it is written: At the tent flap sin crouches (Genesis 4:7)—right then the evil impulse partners with him.
Come and see that it is so! For animals all protect themselves from the day they are born fleeing from fire and all menacing sites; yet a human being is ready at once to fling himself into the fire, because the evil impulse dwells within him, instantly luring him into evil ways.
We have established what is written: Better a poor and wise child than an old and foolish king who no longer knows how to heed warning (Ecclesiastes 4:13). Better a child—יֵצֶר טוֹב (yetser tov), the good impulse, who is a child, just recently with a person, accompanying him only from the age of thirteen, as had been said [see Avot de-Rabbi Natan B, 16; Qohelet Rabbah on 4:13; Midrash Tehillim 9:5; Zohar 1:78a-b (ST), 110b (MhN)].
Than a king—the evil impulse, who is called king, ruling over humanity in the world. Old and foolish, for he is surely old, as already established, since as soon as a person is born, emerging into the atmosphere, he accompanies that person. So he is an old and foolish king [on the link between foolishness and sin, see Numbers 12:11; BT Sotah 3a].
Who no longer knows how לְהִזָּהֵר (le-hizzaher), to heed warning. It is not written לְהַזְהִיר (le-hazhir), to give warning, but rather le-hizzaher, to heed warning—because he is a fool, of whom Solomon said The fool walks in darkness (ibid. 2:14), for he issues from dregs of darkness, deprived of light forever [but he who does not know how to take care of others is not yet considered foolish (Sullam)]…’
Than an old king—the evil impulse, as has been said, for since the first day he existed, he has never escaped defilement. And he is foolish—all his ways evil, leading humans astray, not knowing how to heed warning. He sidles up to people with ploys, luring them from the good way to the evil.
Come and see: This is why he hastens to be with a person from the day he is born, so that he will trust him. For look, when the good impulse arrives, the person cannot believe him—and considers him a burden! Similarly we have learned: Who is cunningly wicked? One who pleads his case in front of the judge before the other party arrives, as is said: The first to plead his case seems right… (Proverbs 18:17, cf. BT Sotah 21b). Similarly this cunning wicked one, as is said: The serpent was cunning (Genesis 3:1)—he arrives first, dwelling with a person before his counterpart comes to rest upon him. Since he appears first, pleading his case with him, when his counterpart—the good impulse—arrives, the person finds him obnoxious and cannot raise his head [cf. Zohar 2:199a: The good impulse, who guides all… said to him, ‘What are you doing sound asleep?’… Repent of your sins!], as if he loaded on his shoulders all the burdens of the world, because of that cunning wicked one who reached him first. Concerning this, Solomon said, The poor man’s wisdom is despised, and his words are not heeded (Ecclesiastes 9:16), because the other anticipated him.
So whoever accepts a person’s words before his counterpart arrives, acts as if he accepts belief in another, false god [see BT Shabbat 105b]. Rather, till the other comes and examines him (Proverbs, ibid.). This is the way of the righteous, for a righteous person does not believe that cunningly wicked evil impulse before his counterpart, the good impulse, arrives. Because of this, people stumble in the world to come.
However, one who is righteous, in awe of his Lord, endures many afflictions in this world so as not to trust and consort with that evil impulse, and the blessed Holy One delivers him from them all, as is written: Many are the afflictions of the righteous, but YHWH delivers him from them all. It is not written Many are רָעוֹת לַצַּדִּיק (ra’ot la-tsaddiq), the afflictions for the righteous, but rather צַדִּיק (tsaddiq), [of] the righteous, because the blessed Holy One אִתְרְעֵי (itre’ei), delights, in that human being and delivers him from everything in this world and in the world that is coming [because the afflictions he suffers alienate him from the evil impulse (Sullam)]. Happy is his share!” (Zohar 1:179a-b, cf. Bahir §163-4).
For He knows יִצְרֵנוּ (yitsrenu), our devisings, recalls that we are dust (Psalms 103:14).
“In the time to come the blessed Holy One will bring the evil impulse and slay it in the presence of the righteous and the wicked. To the righteous it will have the appearance of a towering hill, and to the wicked it will have the appearance of a thread of hair. Both the former and the latter will weep; the righteous will weep saying, ‘How were we able to overcome such a towering hill!’ The wicked also will weep saying, ‘How is it that we were unable to conquer this thread of hair!’ And the blessed Holy One will also marvel together with them, as it is said, Thus says YHWH of Hosts, If it is marvelous in the eyes of the remnant of this people in these days, would it also be marvelous in My eyes? (Zechariah 8:6) [cf. Zohar 1:190b].
Rabbi Assi said, ‘The evil impulse is at first like the thread of a spider, but ultimately becomes like cart ropes, as it is said, Woe unto them that draw guilt with cords of vanity, and sin as it were with a cart rope (Isaiah 5:18).’
Rabbi Avira or, as some say, Rabbi Yehoshua son of Levi, made the following exposition: The evil impulse has seven names. The blessed Holy One called it Evil, as it is said, For the יֵצֶר (yetser), devisings, of the human heart are evil from youth (Genesis 8:21). Moses called it the Uncircumcised, as it is said, Circumcise the foreskin of your heart (Deuteronomy 10:16). David called it Impure, as it is said, A pure heart create for me God (Psalms 51:12) which implies that there is an impure one. Solomon called it the Foe, as it is said, If your foe is hungry, feed him bread, and if he thirsts, give him water, for you would heap live coals on his head, and YHWH will pay you back (Proverbs 25:21); read not, יְשַׁלֶּם-לָךְ (yeshalem-lakh), will pay you back, but יַשׁלִימֶנוּ-לָךְ (yashlimenu-lakh), will cause it to be at peace with you. Isaiah called it the Stumbling-block, as it is said, Heap it up, heap it up, prepare the way, take up the stumbling-block out of the way of My people (Isaiah 57:14). Ezekiel called it Stone, as it is said, And I will take away the stony heart out of your flesh, and I will give you a heart of flesh (Ezekiel 36:26). Joel called it צְּפוֹנִי (Tsefoni), Hidden One, as it is said, But I will remove far off from you אֶת-הַצְּפוֹנִי (et-ha-tsefoni), the northern one (Joel 2:20, cf. Jeremiah 1:14: Out of צָּפוֹן (tsafon), the north, an evil shall break forth).
Our Rabbis taught: But I will remove far off from you the northern one—the evil impulse which is constantly צָפוּן (tsafon), hidden, in the heart of man…
The school of Rabbi Ishmael taught, If this repulsive wretch meets you, drag him to the House of Study. If he is of stone, he will dissolve, if of iron he will shatter [cf. BT Qiddushin 30a]. ‘If he is of stone he will dissolve’—for it is written, Ho, everyone that thirsts, come you to the waters (Isaiah 55:1) and it is written, Water wears away stones (Job 14:19). ‘If he is of iron, he will shatter’—for it is written, Is not My word like a fire? says YHWH; and like a hammer that breaks the rock in pieces? (Jeremiah 23:29).
Rabbi Shemu’el son of Naḥman said in the name of Rabbi Yonatan: the evil impulse seduces you in this world and bears witness against you in the world that is coming, as it is said, Who pampers his slave from youth, in the end there will be מָנוֹן (manon) [alt., מָנוֹד (manod), dismay] (Proverbs 29:21), for according to the [method of letter permutation] א”ט ב”ה (at bah) Rabbi Ḥiyya [teaches] סָהֵדַה (sahadah), witness, is called מָנוֹן (manon). Rav Ḥuna pointed out an incongruity: It is written, For the spirit of harlotry has caused them to err (Hosea 4:12), but is it not also written, [for the spirit of harlotry] is in the midst of them (ibid. 5:4)? First it only causes them to err, but ultimately it enters into them. Rabba observed, ‘First the evil impulse is a wayfarer in the street, then he is called guest, and finally he is called man [of the house], for it is said, And a wayfarer came to the richman, and it seemed a pity to him to take from his own sheep and cattle to prepare for the traveler who had come to him, and he took the poor man’s ewe and prepared it for the man who had come to him [… doomed is the man who has done this! And the poor man’s ewe he shall pay back fourfold, in as much as he has done this thing, and because he had no pity!] (2 Samuel 12:4-6)” (BT Sukkah 52b).