Exodus 11:4-7

4So Moses went to the king and he said, ‘The Lord God says this: “At about midnight, I will travel through the whole country of Egypt.

5I will cause all the firstborn sons in Egypt to die. The firstborn son of Pharaoh, king of Egypt, will die. The firstborn son of the female slave who makes flour, will die. Even the firstborn of the farm animals will die.

6Everyone will be crying loudly in the whole country of Egypt. Nothing like that has ever happened before now, and it will never happen again.

7But no trouble will happen to the Israelite people. Not even a dog will frighten them or their animals. Then you will know that I, the Lord, make a difference between Egypt and Israel.” ’