Exodus 12:1-13, 21-28 (NRSV)
The passover lamb
The Lord said to Moses and Aaron in the land of Egypt: This month shall mark for you the beginning of months; it shall be the first month of the year for you. Tell the whole congregation of Israel that on the tenth of this month they are to take a lamb for each family, a lamb for each household. If a household is too small for a whole lamb, it shall join its closest neighbor in obtaining one; the lamb shall be divided in proportion to the number of people who eat of it. Your lamb shall be without blemish, a year old male; you may take it from the sheep or from the goats. You shall keep it until the fourteenth day of this month; then the whole assembled congregation of Israel shall slaughter it at twilight. 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 lamb that same night; they shall eat it roasted over the fire with unleavened bread and bitter herbs. Do not eat any of it raw or boiled in water, but roasted over the fire, with its head, legs, and inner organs. You shall let none of it remain until the morning; anything that remains until the morning you shall burn. This is how you shall eat it: your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it hurriedly. It is the passover of the Lord. For I will pass through the land of Egypt that night, and I will strike down every firstborn in the land of Egypt, both human beings and animals; 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 live: when I see the blood, I will pass over you, and no plague shall destroy you when I strike the land of Egypt. ...
Then Moses called all the elders of Israel and said to them, "Go, select lambs for your families, and slaughter the passover lamb. Take a bunch of hyssop, dip it in the blood that is in the basin, and touch the lintel and the two doorposts with the blood in the basin. None of you shall go outside the door of your house until morning. For the Lord will pass through to strike down the Egyptians; when he sees the blood on the lintel and on the two doorposts, the Lord will pass over that door and will not allow the destroyer to enter your houses to strike you down. You shall observe this rite as a perpetual ordinance for you and your children. When you come to the land that the Lord will give you, as he has promised, you shall keep this observance. And when your children ask you, 'What do you mean by this observance?' you shall say, 'It is the passover sacrifice to the Lord, for he passed over the houses of the Israelites in Egypt, when he struck down the Egyptians but spared our houses.'" And the people bowed down and worshiped.
The Israelites went and did just as the Lord had commanded Moses and Aaron.
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