Midrash su Deuteronomio 12:21

4) I might think that the entire beast is permitted; it is, therefore, written (Bereshith 9:4): "Only the flesh with its life, its blood, you shall not eat" — ever min hechai (a limb torn from a living animal) is forbidden. (Bereshith 32:33): "Therefore, the children of Israel may not eat the thigh sinew (gid hanasheh)" — the gid hanasheh is forbidden. (Vayikra 7:3): "All fats (cheilev) of ox or sheep or goat you shall not eat" — cheilev is forbidden. (Vayikra 7:26): "And all blood you shall not eat" — blood is forbidden. I might think that they are permitted whether slaughtered (by shechitah) or not slaughtered, (but killed in some other way); it is, therefore, written (Devarim 27:7): "And you shall slaughter (by shechitah) … and you shall eat."

7) "and he shall slaughter it" "and he shall slaughter it" (Vayikra 3:8), "and he shall slaughter it" (Vayikra 3:13): Why three times? Because it is written (Devarim 12:21): "If the place be distant from you in which the L–rd your G d shall choose to place His name, (and you will not be able to come and bring peace-offerings every day, as you can now that the mishkan travels with you), then you shall slaughter of your herd and of your flock … and you shall eat in your gates with all the desire of your soul" — At a distance from the place (i.e., the Temple), you may slaughter (and eat), and not in proximity to the place — to exclude chullin (a non-consecrated animal) from being slaughtered in the azarah.

(Lev. 17:3:) “If any single person from the House of Israel slaughters.” R. Aqiva says, “When Israel was in the desert, they would slaughter cattle by stabbing and eat them; but here the Torah has forbidden it and says to them (ibid.), ‘If any single person from the House of Israel….’⁶⁹Lev. R. 22:7; see Hul. 16b-17a; Sifre, Deut. 12:20 (75). Then it told them, ‘You are forbidden to slaughter apart from the tent of meeting (cf. vs. 4).’” R. Ishmael says, “When Moses said this to them, they were craving to eat meat. At that time, they were cautioned⁷⁰Hizhiru ‘atsman. The verbal expression is used for an explicit biblical prohibition. away from slaughtering, i.e., not to slaughter apart from the tent of meeting.” And why so? It is simply that up to then they had been lusting after idols. Where is it shown that they were slaughtering to idols? Where it is stated (in Lev. 17:7), “And they shall no longer offer sacrifices [to the goat demons after whom they went whoring]….”⁷¹Lev. R. 22:8. When they wished to enter the Land of Israel, they came to Moses. They said to him, “O our master, if we wish to eat flesh, how shall we do so?” He said to them, “In the past, when you were in the desert, you were forbidden to slaughter apart from the tent of meeting; but when you enter the land, you are permitted to slaughter in any place,” as stated (in Deut. 12:20), “When the Lord your God enlarges your territory, as He promised you, [and you say, ‘Let me eat meat, because your soul longs to eat flesh,’ you may eat flesh to your soul's desire].” He said to them, “When I shall have permitted you to slaughter, you may [nonetheless] not take from your flock and slaughter.” Solomon said (in Prov. 27:27), “And there will be enough goat's milk for your food, for the food of your household.” Moses was teaching Israel by saying to them, “If you have sheep, that which you shear is for your clothing,” as stated (in Prov. 27:26), “The sheep will be for your clothes, and the he-goats the reward of a field.” What is the meaning of “and the he-goats the reward of a field?” That whatever you gain as reward from the he-goats that procreate the herd, you are to buy fields with it (i.e., the offspring).⁷²But cf. Hul. 84a. (Prov. 27:27:) “And there will be enough goat's milk,” [meaning] you will have enough goat's milk “for your food, for the food of your household.” R. Aqiva said, “See how the Holy One, blessed be He, cares for the assets of Israel. See what is written (in Deut. 12:21), ‘then you may slaughter from your cattle or flock,’ from what they bear.⁷³T‘Arakh. 4:26. You shall only take and sacrifice from what they give birth to.” Where is it shown? Where it is stated (in Deut. 15:19), “[You shall consecrate to the Lord] all the male firstlings which are born in your herd and in your flock.” You are permitted to sacrifice from what they give birth to. R. Eleazar ben Azariah said, “The Torah has taught you a rule of conduct:⁷⁴T‘Arakh. 4:26; Hul. 84a. If someone from Israel should have ten pounds⁷⁵Gk.: litrai. of silver, let him eat green vegetables in the pot; if he has twenty, let him eat them in a casserole;⁷⁶Gk.: lopas (“flat dish”). if he has thirty, let him eat a pound of meat from Sabbath to Sabbath; and if he has fifty, let him eat meat on each [and every] day.” Now why all this? In order to care for the assets of Israel. R. Eleazar ben Shammua' said, “And when he buys from Sabbath to Sabbath, he should not buy until he consults within his household.” Where is it shown? Because it is so written (in Deut. 12:20), “and you say, ‘Let me eat meat,’” For this reason Moses warned them and gave them a hint (in vs. 21), so that they would not do too much slaughtering.