Exodus 12:5-7

The animal you select must be a one-year-old male, either a sheep or a goat, with no defects. “Take special care of this chosen animal until the evening of the fourteenth day of this first month. Then the whole assembly of the community of Israel must slaughter their lamb or young goat at twilight. They are to take some of the blood and smear it on the sides and top of the doorframes of the houses where they eat the animal.