Exodus 13:1-4

And the Lord spoke to Moses, saying:

Sanctify unto me every firstborn that openeth the womb among the children of Israel, as well of men as of beasts: for they are all mine.

And Moses said to the people: Remember this day in which you came forth out of Egypt, and out of the house of bondage, for with a strong hand hath the Lord brought you forth out of this place: that you eat no leavened bread.