Exodus 12:10-12 New Revised Standard Version (NRSV)
10 You shall let none of it remain until the morning; anything that remains until the morning you shall burn. 11 This is how you shall eat it: your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it hurriedly. It is the passover of the Lord. 12 For I will pass through the land of Egypt that night, and I will strike down every firstborn in the land of Egypt, both human beings and animals; on all the gods of Egypt I will execute judgments: I am the Lord.