Exodus 12:3, 5-6

Speak 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 the house of their fathers, a lamb for an house

Your lamb shall be without blemish, a male of the first year: ye shall take it out from the sheep, or from the goats: 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 in the evening.