In most states killing a dog or a cat is a punishable offense. If you break in to a zoo and kill an animal, you probably will be punished. There are no admonishments in the bible to killing a dog or a cat. This show that laws regarding morals have come into existence without biblical proscription.
According to biblical scholars, Moses must have written the book of LEVITICUS between 1489 and 1451 B.C. (about 3500 years ago). Even given an age for the earth of only 6000 years, that leaves 2500 years before god gave laws to man. Yet in societies before Moses, murder was not allowed. Yes there were killings, yes there was warfare, just as there is today. But societies had laws long before Moses. Indians lived in North and South America with no knowledge of Moses and had laws prohibiting murder, as did the peoples of Africa and the Far East.
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