Yahweh gives instructions to Moses and Aaron for the Israelites to prepare a meal and mark their houses with blood. He kills all the firstborn humans and livestock in Egypt, passing over the homes marked with blood. The Israelites prepare to leave Egypt, collecting gold, silver and clothing from their neighbors and preparing unleavened dough. Yahweh gives instructions to for future generations to celebrate this festival in remembrance.
Exodus 11: The Plague on the Firstborn
Yahweh commands Moses to tell Pharaoh that the firstborn in all of Egypt will die.