TSK · Deuteronomy 16:4

They will eat the meat the same night; they will eat it roasted over the fire with bread made without yeast and with bitter herbs.

For seven days you must eat bread made without yeast. Surely on the first day you must put away yeast from your houses because anyone who eats bread made with yeast from the first day to the seventh day will be cut off from Israel.

“You must not offer the blood of my sacrifice with yeast; the sacrifice from the Feast of Passover must not remain until the following morning.