Exodus 12:4-8

4If any household is too small for a whole lamb, they must share one with their nearest neighbor, having taken into account the number of people there are. You are to determine the amount of lamb needed in accordance with what each person will eat. 5The animals you choose must be year-old males without defect, and you may take them from the sheep or the goats. 6Take care of them until the fourteenth day of the month, when all the members of the community of Israel must slaughter them at twilight. 7Then they are to take some of the blood and put it on the sides and tops of the doorframes of the houses where they eat the lambs. 8That same night they are to eat the meat roasted over the fire, along with bitter herbs, and bread made without yeast.