Exodus 12:5-13

Your lamb shall be without blemish, a male a year old. You may take it from the sheep or from the goats, and you shall keep it until the fourteenth day of this month, when the whole assembly of the congregation of Israel shall kill their lambs at twilight. “Then they shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they eat it. They shall eat the flesh that night, roasted on the fire; with unleavened bread and bitter herbs they shall eat it. Do not eat any of it raw or boiled in water, but roasted, its head with its legs and its inner parts. And you shall let none of it remain until the morning; anything that remains until the morning you shall burn. In this manner you shall eat it: with your belt fastened, your sandals on your feet, and your staff in your hand. And you shall eat it in haste. It is the LORD’s Passover. For I will pass through the land of Egypt that night, and I will strike all the firstborn in the land of Egypt, both man and beast; and on all the gods of Egypt I will execute judgments: I am the LORD. The blood shall be a sign for you, on the houses where you are. And when I see the blood, I will pass over you, and no plague will befall you to destroy you, when I strike the land of Egypt.