Exodus 12:3-6
12:3 Tell the whole community of Israel, ‘In the tenth day of this month they each must take a lamb for themselves according to their families – a lamb for each household.
12:4 If any household is too small for a lamb, the man and his next-door neighbor are to take a lamb according to the number of people – you will make your count for the lamb according to how much each one can eat.
12:5 Your lamb must be perfect, a male, one year old; you may take it from the sheep or from the goats.
12:6 You must care for it until the fourteenth day of this month, and then the whole community of Israel will kill it around sundown.