Exodus 12:18-20 NIV

18 In the first month1 you are to eat bread made without yeast, from the evening of the fourteenth day until the evening of the twenty-first day.

References for Exodus 12:18

19 For seven days no yeast is to be found in your houses. And whoever eats anything with yeast in it must be cut off2 from the community of Israel, whether he is an alien3 or native-born.

References for Exodus 12:19

20 Eat nothing made with yeast. Wherever you live,4 you must eat unleavened bread."5

References for Exodus 12:20