Exodus 12:1-3

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.