Exodus 12:1-9

1 And the LORD spoke unto Moses and Aaron in the land of Egypt, saying,
2 This month shall be unto you the beginning of the months; it shall be the first month of the year to you.
3 Speak unto all the congregation of Israel, saying, In the tenth day of this month let each man take a lamb according to the families of the fathers, a lamb per family;
4 and if the household is too small and is not able to eat the lamb, let him and his neighbour next unto his house take it according to the number of persons; each one according to his eating shall make your count for the lamb.
5 The lamb shall be without blemish, a male of one year; ye shall take it out from the sheep or from the goats;
6 and ye shall keep it up until the fourteenth day of the same month, and the whole assembly of the congregation of Israel shall kill it between the two evenings.
7 And they shall take of the blood and put it on the two side posts and on the upper door post of the houses in which they shall eat it.
8 And they shall eat the flesh in that night, roasted with fire, and unleavened bread; and with bitter herbs they shall eat it.
9 Eat none of it raw, nor boiled at all with water, but roast with fire, his head with his legs, and with the entrails thereof.