Exodus 8:26

The abomination of the Egyptians] Animal worship was very prevalent in Egypt, certain kinds of animals being regarded as peculiarly sacred and on no account to be slaughtered. For the Israelites to sacrifice cattle, sheep, and goats would be to outrage the religious feelings of the Egyptians, and might lead to war and bloodshed. That Moses had good grounds for his fear on this account cannot be questioned. Diodorus, the historian, tells of a Roman ambassador who was put to death for accidentally killing a cat. A modern instance of the danger of offending religious prejudices may be seen in the Indian Mutiny, which is said to have been occasioned by the serving out of greased cartridges to the Bengal troops. The end of the cartridge was usually bitten off before being inserted in the musket, and of this these men, who were Hindus and forbidden by their religion to eat cow's flesh, had a superstitious abhorrence.