In the old books of the Hebrew Bible there is a book called Leviticus. Its name means "about the Levites," the family of priests who served at the altar, and most of the book is their rule list: which animals to kill, how to wash, what to eat. Then, in the middle of all those rules, there is a line that sounds like it came from somewhere else.
Thou shalt love thy neighbour as thyself. (Leviticus 19:18)
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