Exodus 12:24-30

And ye shall observe this thing for an ordinance to thee and to thy sons for ever. And it shall come to pass, when ye are come to the land which Jehovah will give you, according as he hath promised, that ye shall keep this service. And it shall come to pass, when your children shall say unto you, What mean ye by this service? that ye shall say, It is the sacrifice of Jehovah’s passover, who passed over the houses of the children of Israel in Egypt, when he smote the Egyptians, and delivered our houses. And the people bowed the head and worshipped. And the children of Israel went and did so; as Jehovah had commanded Moses and Aaron, so did they. And it came to pass at midnight, that Jehovah smote all the first-born in the land of Egypt, from the first-born of Pharaoh that sat on his throne unto the first-born of the captive that was in the dungeon; and all the first-born of cattle. And Pharaoh rose up in the night, he, and all his servants, and all the Egyptians; and there was a great cry in Egypt; for there was not a house where there was not one dead.