Our Torah portion’s title comes from the opening account that, on the eighth day after their seven days of consecration, Aaron and his sons entered upon their priestly duties. Almost immediately afterwards follows a narrative of the death of Aaron’s two eldest sons, who “offered strange fire upon God’s altar which the Almighty did not command them to do.” Here is a story that is typical of ancient literature seeking to stress the importance of taboo, and of the dangers of confusing the sacred and the profane.
The rest of the ‘sedrah’ focuses on the laws of clean and unclean animals. Here are detailed lists of the kinds of animals that may be eaten by an Israelite, and they include only the following. Vertebrates: only mammalian ungulates (split hoofed and cud chewers); birds which are not carnivorous, and fish with scales and fins. Other kinds of vertebrate animals, such as reptiles, amphibians, shark-like creatures, are strictly forbidden.