Exodus 12:1-6

1And Jehovah spake unto Moses and Aaron in the land of Egypt, saying,

2This month shall be unto you the beginning of months: it shall be the first month of the year to you.

3Speak ye unto all the congregation of Israel, saying, In the tenth day of this month they shall take to them every man a lamb, according to their fathers’ houses, a lamb for a household:

4and if the household be too little for a lamb, then shall he and his neighbor next unto his house take one according to the number of the souls; according to every man’s eating ye shall make your count for the lamb.

5Your lamb shall be without blemish, a male a year old: ye shall take it from the sheep, or from the goats:

6and ye shall keep it until the fourteenth day of the same month; and the whole assembly of the congregation of Israel shall kill it at even.