“And you shall ritually slaughter from your cattle and your sheep as I have commanded you” (Devarim 12,21)
It is a positive commandment that anyone who wishes to eat the flesh of a domestic animal, wild animal or fowl, must first slaughter them in the correct way. Concerning this it says “and you shall ritually slaughter from your cattle and your sheep as I have commanded you”.
Even though the verse only mentions cattle and sheep, there is a rule in the entire Torah that wild animals are included in the category “animal” and fowl is also categorised with animals as it says “this is the law of the animal and fowl.” However, fish do not require ritual slaughter as it says “all the fish of the sea may be gathered for them” i.e. fish are permitted after being gathered, even if they were gathered after they died. So too, any type of locust does not require ritual slaughter for about them the verse also says “the gathering of the locust”.
The reasons for the commandment are that since the Torah has extensively forbidden the consumption of blood, and the blood of the body comes out of the neck more than from the other parts of the body, therefore we have been commanded to ritually slaughter animals at that point of the body before we eat them because all of their blood will come out from there and we may not eat the soul with the flesh. Furthermore, it says, that the reason for ritual slaughter from the neck with an inspected knife is so as not to cause too much pain to living creatures for the Torah has permitted them to mankind for consumption or for other needs due to man’s eminence, but has not permitted us to cause them unnecessary pain.
This commandment applies in every place, at every time, to men and to women for even women are commanded not to eat (meat) without ritual slaughter. Ritual slaughter is permitted by any man as long as he is sufficiently knowledgeable in the laws of ritual slaughter.
One who is not careful to refrain from eating the flesh of an animal, wild animal or bird which were not ritually slaughtered has transgressed this positive commandment, apart from having transgressed the negative commandment of “You shall not eat any dead carcass”.