Moses said, "Thus says the Lord: Toward midnight I will go forth among the Egyptians, and every first-born in the land of Egypt shall die, from the first-born of Pharaoh who sits on his throne to the first-born of the slave girl who is behind the millstones; and all the first-born of the cattle. And there shall be a loud cry in all the land of Egypt, such as has never been or will ever be again; but not a dog shall snarl at any of the Israelites, at man or beast--in order that you may know that the Lord makes a distinction between Egypt and Israel. Then all these courtiers of yours shall come down to me and bow low to me, saying, 'Depart, you and all the people who follow you!' After that I will depart." And he left Pharaoh's presence in hot anger.
Now the Lord had said to Moses, "Pharaoh will not heed you, in order that My marvels may be multiplied in the land of Egypt." Moses and Aaron had performed all these marvels before Pharaoh, but the Lord had stiffened the heart of Pharaoh so that he would not let the Israelites go from his land.
The Lord said to Moses and Aaron in the land of Egypt: This month shall mark for you the beginning of the months; it shall be the first of the months of the year for you. Speak to the whole community of Israel and say that on the tenth of this month each of them shall take a lamb to a family, a lamb to a household. But if the household is too small for a lamb, let him share one with a neighbor who dwells nearby, in proportion to the number of persons: you shall contribute for the lamb according to what each household will eat. Your lamb shall be without blemish, a yearling male; you may take it from the sheep or from the goats. You shall keep watch over it until the fourteenth day of this month; and all the assembled congregation of the Israelites 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 are to eat it. They shall eat the flesh that same night; they shall eat it roasted over the fire, with unleavened bread and with bitter herbs. Do not eat any of it raw, or cooked in any way with water, but roasted--head, legs, and entrails--over the fire. You shall not leave any of it over until morning; if any of it is left until morning, you shall burn it.
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 a passover offering to the Lord. For that night I will go through the land of Egypt and strike down every first-born in the land of Egypt, both man and beast; and I will mete out punishments to all the gods of Egypt, I the Lord. And the blood on the houses where you are staying shall be a sign for you: when I see the blood I will pass over you, so that no plague will destroy you when I strike the land of Egypt.
This day shall be to you one of remembrance: you shall celebrate it as a festival to the Lord throughout the ages; you shall celebrate it as an institution for all time. Seven days you shall eat unleavened bread; on the very first day you shall remove leaven from your houses, for whoever eats leavened bread from the first day to the seventh day, that person shall be cut off from Israel.
You shall celebrate a sacred occasion on the first day, and a sacred occasion on the seventh day; no work at all shall be done on them; only what every person is to eat, that alone may be prepared for you. You shall observe the [Feast of] Unleavened Bread, for on this very day I brought your ranks out of the land of Egypt; you shall observe this day throughout the ages as an institution for all time. In the first month, from the fourteenth day of the month at evening, you shall eat unleavened bread until the twenty-first day of the month at evening. No leaven shall be found in your houses for seven days. For whoever eats what is leavened, that person shall be cut off from the community of Israel, whether he is a stranger or a citizen of the country. You shall eat nothing leavened; in all your settlements you shall eat unleavened bread.