Exodus 12:18-20

Young's Literal Translation

¹⁸ `In the first [month], in the fourteenth day of the month, in the evening, ye do eat unleavened things until the one and twentieth day of the month, at evening;

¹⁹ seven days leaven is not found in your houses, for any [one] eating anything fermented -- that person hath been cut off from the company of Israel, among the sojourners or among the natives of the land;

²⁰ anything fermented ye do not eat, in all your dwellings ye do eat unleavened things.'