Exodus 12:5-13

The animals you choose must be year-old males without defect, and you may take them from the sheep or the goats. Take care of them until the fourteenth day of the month, when all the members of the community of Israel must slaughter them at twilight. Then they are to take some of the blood and put it on the sides and tops of the doorframes of the houses where they eat the lambs. That same night they are to eat the meat roasted over the fire, along with bitter herbs, and bread made without yeast. Do not eat the meat raw or boiled in water, but roast it over a fire—with the head, legs and internal organs. Do not leave any of it till morning; if some is left till morning, you must burn it. This is how you are to eat it: with your cloak tucked into your belt, your sandals on your feet and your staff in your hand. Eat it in haste; it is the LORD’s Passover. “On that same night I will pass through Egypt and strike down every firstborn of both people and animals, and I will bring judgment on all the gods of Egypt. I am the LORD. The blood will be a sign for you on the houses where you are, and when I see the blood, I will pass over you. No destructive plague will touch you when I strike Egypt.