Exodus 12:26-27

26Now when it happens that your children ask you, ‘What does this ceremony mean to you?’

27You are to say, ‘It is the sacrifice of Adonai’s Passover, because He passed over the houses of Bnei-Yisrael in Egypt, when He struck down the Egyptians, but spared our households.’” So the people bowed their heads and worshipped.