Exodus 12:3-7

Speak to all the congregation of Israel, saying, ‘On the tenth of this month they are, each one, to take a lamb for themselves, according to the fathers’ households, a lamb for each household.

Now if the household is too small for a lamb, then he and his neighbor nearest to his house are to take one according to the number of persons in them; in proportion to what each one should eat, you are to divide the lamb.

Your lamb shall be an unblemished male a year old; you may take it from the sheep or from the goats.

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.

Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel of the houses in which they eat it.