Exodus 12:1-6

The LORD said to Moses and Aaron in the land of Egypt, “This month shall be the beginning of months to you; it is to be the first month of the year to you. Tell all the congregation of Israel, ‘On the tenth [day] of this month they are to take a lamb or young goat for themselves, according to [the size of] the household of which he is the father, a lamb or young goat for each household. Now if the household is too small for a lamb [to be consumed], let him and his next door neighbor take one according to the number of people [in the households]; according to what each man can eat, you are to divide the lamb. Your lamb or young goat shall be [perfect] without blemish or bodily defect, a male a year old; you may take it from the sheep or from the goats. [1 Pet 1:19, 20] You shall keep it until the fourteenth day of the same month, then the whole assembly of the congregation of Israel is to slaughter it at twilight.