Exodus 13:8

And thou shall show thy son in that day,.... On the first of the days of the feast of unleavened bread, the reason of eating it; and this is to be shown not to a son or single child only, but by parents to all their children, sons and daughters, and even unasked, as Maimonides b interprets it; and so Jarchi's note is, to a son that knows not how to ask or what to ask about, Exodus 12:26 Exodus 12:27:

saying, this is done because of that which the Lord did unto me, when I came forth out of Egypt: that is, this unleavened bread is eaten because of the quick and speedy deliverance of Israel out of Egypt, so that they had not time to leaven their dough.

b Hilchot Chametz Umetzah, c. 7. sect. 2, 3.