Leviticus Chapters 11-12
We know the Lord handed down numerous "laws" to the Israelite people in the first two years following the exodus from Egypt, and at the start of the 40 years in the wilderness before they reached Canaan.
There has been much debate by religious scholars as to "why" the Lord made such unique and specific legal requirements of His chosen people. Most generally agree He wanted His people to be "holy" in observance of His holiness. It clearly was the Lord’s decision, according to His purpose, and His legal instructions left little doubt as to their clarity in terms of understanding.
The Israelites exact following (or not following) of those specific laws would created many problems over the subsequent years. They all fell short of the glory of God.
After instructions regarding the priesthood, the Lord, as stated in the 11th and 12th chapters of Leviticus then gave Moses and Aaron specific instructions regarding two major areas of daily living for the Israelites.
First, the Lord instructed them with regard to which foods were lawful for the Israelites to eat, and which were "unclean". Next, the Lord provided directions regarding the time period of purification following childbirth.
The Lord created an unusual distinction between the different animals and creatures which were allowable to eat: as "clean" and all the remainder were "unclean" and could not be eaten. This division of foods is the origination of the current Jewish term "kosher". Many devout Jews still observe this distinction in edible foods. The basic distinction involved animals free of dirt or filth, and thus leading to moral purity. Ruled out were any animals already dead onto themselves, or killed by birds of prey.
"There are the beasts which ye shall eat among all the beasts that are on the earth," the Lord told Moses and Aaron to instruct the people. Lev. 11:2. The basic rule for large animals was that the people could eat an animal that "parteth the hoof and is clovenfooted, and cheweth the cud..." Lev. 11:3.
Both the foot had to be divided and the animal had to chew the cud. Therefore, the cow was acceptable, but the camel and pig were not, as well as most large mammals such as elephants and hippos, etc. One specific animal listed as unacceptable at Lev. 11:5 was the "coney". The coney was a small rabbit-like animal (rock badger) common to the Middle East dessert.
In seafood, the animals had to have both fins and scales to be edible. Basic fish were acceptable, but shrimp, shark, octopus, serpent-like sea animals, etc were not.
As far as birds, many were forbidden, especially any birds of prey or those that were marsh birds, including certain classes of birds such as eagles, hawks, vultures, ravens, owls, swans, pelican, stork and the bat. Permitted were flying animals that "go on all four, which have legs above their feet to leap" around.
Another category unacceptable were animals that "creepeth" upon the earth as were many types of mammals and reptiles (weasels, mice, turtles, lizards, snakes, snails moles, etc.) bugs and insects and worms.
The "unclean" were not be be eaten or touched when dead. Forbidden was the use of pots and dishes and clothes that touched such animals.
Also forbidden was the consumption of the blood of animals.
The reason for this division of food appears at Lev. 11:44-45 in a statement from the Lord: "For I am the Lord God: ye shall therefore sanctify yourselves, and ye shall be holy; for I am holy: neither shall ye defile yourselves with any manner of creeping thing that creepeth upon the earth." ... "ye shall therefore by holy, for I am holy."
In the 12th chapter of Leviticus, the Lord spoke to Moses regarding purification of the unclean after childbirth. Because apparently of the blood and other post-birth secretions, the mother was in need of purification of her body.
The Lord instructed Moses regarding the time periods for men to be with their wives following childbirth following the birth of a male child, with a different time period for female childbirths.
For male children, the child was to be circumcised on the eighth day.
Following the time period for purification, the mother was then to provide a sacrifice to the Lord as a sin offering to the Lord for atonement so that "she shall be cleansed from the issue of her blood."