Exodus 12:3, 5-6, 11

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.

Your lamb or young goat shall be [perfect] without blemish or bodily defect, a male a year old; you may take it from the sheep or from the goats. [1 Pet 1:19, 20] 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.

Now you are to eat it in this manner: [be prepared for a journey] with your loins girded [that is, with the outer garment tucked into the band], your sandals on your feet, and your staff in your hand; you shall eat it quickly—it is the LORD’S Passover.