'Yeast' in the Bible

You must not eat any yeast with it. Instead, for seven days eat bread without yeast the bread of affliction because you left the land of Egypt in haste. Remember the day you went out of the land of Egypt for the rest of your lives.

No yeast is to be found anywhere in your territory for seven days, and none of the meat you sacrifice in the evening of the first day is to remain until morning.

Eat bread without yeast for six days. Then on the seventh day, hold an assembly to the LORD your God. Don't do any work."