'Yeast' in the Bible

You must eat unleavened bread for seven days. On the first day you must remove yeast from your houses. Whoever eats what is leavened from the first day through the seventh day must be cut off from Israel.

Yeast must not be found in your houses for seven days. If anyone eats something leavened, that person, whether a foreign resident or native of the land, must be cut off from the community of Israel.

The people baked the dough they had brought out of Egypt into unleavened loaves, since it had no yeast; for when they had been driven out of Egypt they could not delay and had not prepared any provisions for themselves.

Unleavened bread is to be eaten for those seven days. Nothing leavened may be found among you, and no yeast may be found among you in all your territory.