Exodus 11:1-6

And the LORD said unto Moses, Yet will I bring one plague more upon Pharaoh, and upon Egypt; afterwards he will let you go hence: when he shall let you go, he shall surely thrust you out hence altogether. Speak now in the ears of the people, and let every man borrow of his neighbour, and every woman of her neighbour, jewels of silver, and jewels of gold. And the LORD gave the people favour in the sight of the Egyptians. Moreover the man Moses was very great in the land of Egypt, in the sight of Pharaoh's servants, and in the sight of the people. And Moses said, Thus saith the LORD, About midnight will I go out into the midst of Egypt: and all the firstborn in the land of Egypt shall die, from the firstborn of Pharaoh that sitteth upon his throne, even unto the firstborn of the maidservant that is behind the mill; and all the firstborn of beasts. And there shall be a great cry throughout all the land of Egypt, such as there was none like it, nor shall be like it any more.