“Resh Lakish said: ‘… If one comes to defile himself, the door is opened to him; if one comes to purify himself, he is assisted.’ … It was taught in the school of Rabbi Yishma’el: ‘Sin dulls [or: obstructs] a person’s לֵב [lev], heart, as is said: Do not become impure with them, וְנִטְמֵתֶם (ve-nitmetem), becoming impure, through them (Leviticus 11:43). Do not read וְנִטְמֵתֶם (ve-nitmetem), becoming impure, but rather וְנִטַּמְתֶּם (ve-nitamtem), becoming dulled [or: obstructed]'” (BT Yoma 38b).
“It is written: You shall sanctify yourselves and be holy… (Leviticus 11:44). If one comes to defile himself, he is surely defiled. And it is written: וְנִטְמֵתֶם (ve-nitmetem), becoming impure, through them (ibid., 43)—[spelled unconventionally] without an א: totally obstructed impurity, which cannot be purified as can other types of impurity. Furthermore, he is terrified of dangerous beasts, for in their eyes he appears as a kid and he is vulnerable, being divested of the human image [cf. BT Shabbat 151b; Shir ha-Shirim Rabbah on 3:7]. Rabbi Yeisa permitted the eating of chicken with dairy cheese [cf. BT Shabbat 130a]. Rabbi Shim’on said, ‘This is surely forbidden to you! One should not provide an opening for evil species. ‘Go, O Nazarite,’ one says, ‘around; do not approach the vineyard!’ This is surely forbidden to you, since it entails the same stricture as cattle. What is written of one who permits this? You gave the Nazarites wine to drink (Amos 2:12)—permitting this is like permitting that. And it is written: You shall not eat any abhorrent thing (Deuteronomy 14:3)—any includes everything” (Zohar 2:125b).
“Now, you might say, ‘What about the goat, upon which settles an impure spirit? Not so! For if an impure spirit settled upon it, we would be forbidden to eat it. Rather, they pass through them and manifest in front of them, yet do not settle within them; for as they settle, another spirit passes over them and they disengage from their bodies. So they appear in front of them and harass within them, yet do not possess their bodies—which we are therefore permitted to eat.
Whether cattle, beasts, birds, or fish of the sea—among all of them appear right and left, Compassion and Judgment. Whatever comes from the side of the right, the side of Compassion, we are permitted to eat; and all those coming from the side of the left, the side of Judgment, we are forbidden to eat [forbidden animals are predators, scavengers, and bottom feeders not worthy of emulation]—for all their bodies are impure and they all defile; an impure spirit settles within them, dwelling in them. Therefore, the holy spirit of Israel must not mingle with them nor be defiled by them, so that they may remain holy and be recognized above and below. Happy is their share, for the Holy King delights in them and seeks to purify and sanctify them above all, for they are linked to Him!
… Whoever eats of those forbidden foods clings to the Other Side and makes his soul and his body loathsome. An impure spirit settles upon him, and he demonstrates that he has no share in the supernal King and does not come from His side nor cleave to Him. If he departs like this from the world, he is seized by all those linked to the side of impurity, who defile him—punishing him as a person loathed by his Lord, loathed in this world and loathed in the world that is coming.
Of this is written וְנִטְמֵתֶם (ve-nitmetem), becoming impure, through them (Leviticus 11:43)—without an א, for there is no remedy for his loathsomeness, and he never emerges from impurity. Woe to them, woe to their souls, for they will never cling to the Bundle of Life because they have been defiled! Woe to their bodies, of which is written For their worm will not die, nor will their fire be quenched, and they will be a horror to all flesh (Isaiah 66:24). What is a horror? A stench. Who causes this? That side to which they clung” (Zohar 3:41b).
“Rabbi Abba said: I have remembered a certain matter I heard from the Holy Lamp who heard it in the name of Rabbi Eli’ezer. One day a clever gentile came and said to him: Old man, old man… you say that you are closer to the divine King than all other peoples. Whoever is close to the King is forever rejoicing, without pain, without fear, without troubles. But you are perpetually in pain, trouble and agony, more than anyone else. Look at us—no pain, trouble nor agony approaches us at all, from whence it follows that we are close to the divine King and you are far from Him, and this is why you have pain and trouble and sorrow and agony, which we do not have.
Further: You do not eat of an animal found dead nor one not ritually slaughtered so that you will be healthy and your body healthy. We eat anything we want and we are physically strong and healthy and all our limbs are fit. You do not eat and all are sick with bad illnesses and broken more than all other peoples. You are a people whom YHWH hates above all. Old man, old man, do not say anything to me because I shall not listen to you, nor accept it from you. Rabbi Eli’ezer lifted up his eyes, looked at him, and turned him into a heap of bones [cf. Proverbs 18:2: A fool does not care for discerning but for exposing his inner thoughts; ibid., 26:4-5: Do not answer a dolt by his folly, lest you, too, be like him. Answer the dolt by his folly, lest he seem wise in his own eyes].
When his anger had subsided, he looked back, cried, and said: YHWH, our Master, how majestic Your name in all the earth! (Psalms 8:2). How strong is the power of the holy and mighty name in all the earth, and how beloved are words of Torah, for nothing is so minor that it will not be found in Torah, and even the smallest thing in Torah issued from the mouth of the blessed Holy One. Those matters that that wicked one asked, I too, once asked of Elijah, and he replied that in the academy of the firmament [these very matters] were laid out before the blessed Holy One, as follows…
Israel do not partake of animals found dead or those not ritually slaughtered, nor of filth and dirt of reptiles and insects as do other peoples, [but are nevertheless weaker than they are]. This is so. For the לֵב [lev], heart, which is soft and weak and is the king and the sustenance of the other limbs, does not take for its nourishment other than from the clearest and purest of all the blood, and its food is clean and clear and is softer and weaker than all the rest. And it leaves the remaining waste matter for the other limbs, and the other limbs are not concerned, but take all that waste, even the worst, and they are strong as befits them. This is why all the other limbs have skin eruptions and scabs, bright spots and leprous boils, and the heart has none of them, for it is clean and clear, and has no blemish whatsoever. Thus the blessed Holy One, took Israel, who is clean, clear, and without blemish, for Himself, as it says: You are entirely beautiful, my love, and there is no flaw in you [Song of Songs 4:7]. Rabbi Yose came, kissed his hands, and said: If I had come into the world just to hear this, it would have been sufficient” (Zohar Pinḥas).