“[Suffering] came to Rabbi [Yehudah ha-Nasi] because of an incident. What was it? A calf was being lead to slaughter, [when] he went and hung his head on the corner of the Rabbi [‘s garment], and moaned. He said to him, ‘Go, you were made for this!’ They said [in the heavenly court], ‘Since he has no mercy, let suffering overtake him.’
And [suffering] departed because of [another] incident. How so? One day Rabbi’s maidservant was sweeping the house. [Seeing] some young weasels lying there, she went to sweep them away. He said to her, ‘Let them be. It is written, His mercy is over all His works (Psalms 145:9).’ They said, ‘Since he has mercy, let us be merciful to him’” (BT Bava Metsi’a 85a, cf. Ḥakham Yosef Ḥayyim of Baghdad, Ben Yehoyada).
“Let me give you a great key. Why did God, may He be blessed, see fit to issue a commandment in the Torah to slaughter animals for man’s food? Is it not written, YHWH is good to all and His mercy is over all His works (Psalms 145:9). If He is indeed merciful, how could He command to slaughter this animal for man’s food? Where is His mercy? But the mystery of this verse comes in its first clause, which says, YHWH is good to all—good, indeed, and therefore, His mercy is over all His works. This is the explanation: In the Workings of Creation, it was predetermined that this particular animal was to be slaughtered and the animal said ‘good.’ What is the reason for this? The animal does not have a supernal נְשָׁמָה (neshamah), soul [but only a נֶפֶשׁ (nefesh), life-breath, see Genesis 1:24, cf. Leviticus 17:11] that could grasp God and His mighty works.
So God decreed during the creation of the world that all of the animals should be brought before Him, and He said, ‘Do you wish to be slaughtered and eaten by man so that you will rise from the rung of an animal, knowing nothing, to the rung of a human who knows and recognizes YHWH, may He be blessed?’ And the animals responded, ‘Good, and mercy will be upon us.’ For when man eats from a part of the animal, he becomes a part of man. Thus, animal becomes human and his slaughter is merciful, for he has left the rung of animal and entered the rung of human. In this way, a man’s death is life for him, for he ascends to the rung of the angels. And this is the mystery of YHWH saves man and beast (Psalms 36:7). If this is so, understand the essence of slaughtering animals, as it is all from His abundant mercy and graciousness upon all His creatures. For this reason, consider that which the Rabbis said: ‘An ignoramus is forbidden to eat meat [for it is said, This is the תּוֹרַת (torat), teaching, about beast and bird (Leviticus 11:46)]’ (BT Pesaḥim 49b) [cf. Sefer ha-Qanah 120r], since He commanded in the Torah that only he who knows the teaching concerning domesticated beasts, wild animals, and fowl may slaughter [animals]. He who is engaged in Torah is permitted to eat meat and he who is not engaged in Torah is forbidden to eat meat. Therefore, an ignoramus may not eat meat for he is like an animal, without a neshamah, soul, and He did not command that an animal should be slaughtered to be eaten by another animal” (Rabbi Yosef Gikatilla, Sha’arei Orah, Sha’ar ha-Shishi, Sefirah ha-Ḥamishit).
“Before Adam sinned, what was written? God said, ‘Look, I have given you every [seed-bearing] plant…’ (Genesis 1:29), and to you it shall be for food (ibid.), but nothing more. After he sinned and the evil impulse had been absorbed into his body and that of his descendants, He executed judgment upon them.
Afterward, Noah came and perceived that the body was built upon the pervasive evil impulse. He offered a sacrifice just as Adam did. What is written? YHWH smelled the pleasing aroma… since the devisings of the human heart are evil from youth (Genesis 8:21). The blessed Holy One said, ‘From now on, since his body has been imbued with the evil impulse, let the body enjoy as much as a person sees fit—let him eat meat [cf. Deuteronomy 12:20: when your appetite craves eating meat, wherever your appetite’s craving may be, you shall eat meat].
Like the green plants, I have given all to you (ibid. 9:3). When he eats meat, his own flesh delights from that flesh, and they intermingle. His body swells as a result; and on account of the pleasure the body sins copiously. Thus, the blessed Holy One said, atonement for the body—with flesh. Meat that a person eats produces blood for the body. Blood remaining from that meat—drained—is designated for atonement for blood, manufactured from its own flesh. This is as is written: it is the blood that gains atonement through the soul (Leviticus 17:1)” (Zohar 1:89b, Sitrei Torah, cf. BT Sanhedrin 59b in the name of Rav Yehudah).
“Flesh is garment of the human, as is written everywhere: flesh of a human (Exodus 30:32)—human, within; flesh, garment of the human, it’s body.
Specters below, melted in the smelting of this spirit, were figured into figures clothed in another garment, such as figures of pure animals: ox, sheep, goat, deer, gazelle, roebuck, wild goat, ibex, antelope, and mountain sheep (Deuteronomy 14:4–5), who desire to be interwoven in the garment of the human, flesh of the human” (Zohar 1:20b).
“And the reason for Split hooves… bringing up the cud (Leviticus 11:3) is according to the plain sense. These signs are the reason for [them being] clean or unclean [or: pure or impure]…. And there are [those among] the latest kabbalists [such as Rabbi ‘Yosef who came from the city of Shushan’ (i.e., from Hamadan in Persia)] who believe in גִּלְגּוּל הַבְּהֵמוֹת (gilggul ha-behemot), ‘the rolling of beasts.’ And they say that if a man committed a certain heinous transgression beyond [what] his merits [can protect him from, his nefesh, life-breath] will roll into an unclean beast, this is as is said, And they do not bring up the cud, they are unclean for you (ibid., 26)—he who has no ‘cud,’ beyond his merits. And if he [does] ‘bring up the cud,’ over his merits [i.e., preserves his merits and pays the price of punishment] he will roll into a clean beast. Only, if the offence [be] idolatry, forbidden sexual relations, [or] spilling blood, with these three even if ‘he brings up the cud’ he will roll into uncleanness—if he does not return in repentance. This is the mystery of hare, camel, pig:
The mystery of שָׁפָן (shafan), hare, is ‘שֶׁפָּנָה (she-panah), that he turned’—to idolatry. גָּמָל (Gamal), camel, comes regarding forbidden sexual relations, as is said, חָסֶד (Ḥased), a vile, man, גֹּמֵל (gomel), does for, himself, [and a cruel man blights his own flesh] (Proverbs 11:17). And of forbidden sexual relations, is written, [And a man who takes his sister…] it is חֶסֶד (ḥesed), vileness, and they shall be cut off (Leviticus 20:17) [the incest laws are found together with prohibitions on homosexuality, bestiality, and child sacrifice, see Leviticus 18]. Of the mystery of חֲזִיר (ḥazir), pig, is said, חֲזִיר (Ḥazir), the boar, from the forest has gnawed it, [and the swarm of the field fed upon it] (Psalms 80:14)—הַמַּחֲזִיר (ha-maḥazir), the one who ‘returns [i.e., spills], blood,’ on the ground [cf. BT Niddah 13a–b; Zohar 1:188a, 219b]. With these three even if his merits are greater than his crimes, which are ‘brought up cud,’ with more mitsvot than transgressions, or they are in between—mystery of מַפְרִיסֵי פַּרְסָה (mafrisei parsah), split hoof (Leviticus 11:4), from the expression פְּרָס (peras), reward, they roll into uncleanness. Recall what is said: But this you shall not eat from those that bring up the cud or have hooves (Leviticus 11:4) [see BT Bekhorot 6a–b ad loc.]. And therefore they said of the Torah [prohibitions] that any food from them is as if [derived from] the flesh of his companion who was defiled by transgressions, blessed is he who knows truth [cf. Rabbi Yosef Hamadan, Sefer Tashak, 92]. And already you know what our Rabbis, of blessed memory, expounded: ‘Why did he call its name חֲזִיר (ḥazir), pig? Because the blessed Holy One is destined לְהַחֲזִירוֹ (le-haḥaziro), to return it, to us’ [see Rabbi Yom Tov ben Avraham Ishbili on BT Qiddushin 49b; cf. Midrash Tehillim 146:4]” (Rabbi Menaḥem Recanati, Perush al ha-Torah, Parashat Shemini, cf. Sa’adia Gaon, Kitāb al-Amanāt wal-I‘Tiqadāt, 6:8).
“It was said that fish and locusts do not require slaughter, but rather, their gathering makes them permitted [and fit to eat, see BT Ḥullin 27b]. Such are Masters of Mishnah, they do not need slaughter, but rather, it is said of them, And was gathered to his kinfolk (Genesis 49:33). Fish of the sea live in the sea. Disciples of the Sages and Masters of Mishnah live in Torah. And if they are separated from her they die immediately” (Zohar 3:278b, Ra’aya Meheimna Ki Tetse, cf. TZ 21, 59a).