Deuteronomy 16:3-8

Do not eat it with bread made with yeast, but for seven days eat unleavened bread, the bread of affliction, because you left Egypt in haste—so that all the days of your life you may remember the time of your departure from Egypt. Let no yeast be found in your possession in all your land for seven days. Do not let any of the meat you sacrifice on the evening of the first day remain until morning. You must not sacrifice the Passover in any town the LORD your God gives you except in the place he will choose as a dwelling for his Name. There you must sacrifice the Passover in the evening, when the sun goes down, on the anniversary of your departure from Egypt. Roast it and eat it at the place the LORD your God will choose. Then in the morning return to your tents. For six days eat unleavened bread and on the seventh day hold an assembly to the LORD your God and do no work.