Exodus 12:5-13

Your lamb shall be without blemish, a male of the first year. You may take it from the sheep or from the goats. Now you shall keep it until the fourteenth day of the same month. Then the whole assembly of the congregation of Israel shall kill it at twilight. And they shall take some of the blood and put it on the two doorposts and on the lintel of the houses where they eat it. Then they shall eat the flesh on that night; roasted in fire, with unleavened bread and with bitter herbs they shall eat it. Do not eat it raw, nor boiled at all with water, but roasted in fire—its head with its legs and its entrails. You shall let none of it remain until morning, and what remains of it until morning you shall burn with fire. And thus you shall eat it: with a belt on your waist, your sandals on your feet, and your staff in your hand. So you shall eat it in haste. It is the LORD’s Passover. ‘For I will pass through the land of Egypt on that night, and will strike all the firstborn in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgment: I am the LORD. Now 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 the plague shall not be on you to destroy you when I strike the land of Egypt.