Do Not Eat Leaven on Passover
The Memory Commandment — Why Chametz Is Forbidden on Passover
Exodus 13:3: “Remember this day in which you came out from Egypt, out of the house of slavery, for by a strong hand the LORD brought you out from this place. No leavened bread shall be eaten.” The verse frames the chametz prohibition not as a dietary rule but as an act of memory. The Exodus was accomplished in haste — no time for bread to rise (Exodus 12:39: “for it had not leavened, because they were thrust out of Egypt and could not wait”). The prohibition on chametz re-enacts this haste every year: for seven days, Israel returns to the bread of urgency, the bread of a people who left Egypt without waiting for their dough to rise. Chametz is the bread of ordinary Egypt; matzah is the bread of the Exodus.
The connection between chametz and Egypt runs deeper than bread type. Chametz, in the rabbinic imagination, represents the yetzer hara — the inclination toward comfort, complacency, and spiritual inflation. The bread that rises is the bread of settled life; the flat bread is the bread of the journey. Passover’s seven days of matzah force a reset: remove the risen bread, eat the flat bread, remember what it was to be a people moving rather than settled, dependent on God rather than on Egypt’s granaries.
Seven Days of Abstention — The Scope of the Prohibition
Exodus 12:15: “Seven days you shall eat unleavened bread; on the first day you shall put away leaven from your houses, for whoever eats leavened bread from the first day to the seventh day, that person shall be cut off from Israel.” The seven-day duration is not incidental — it is the full span of the festival, from the 15th through the 21st of Nissan (with a rabbinic extension to the 22nd in the Diaspora). Unlike a single-day fast or prohibition, the chametz ban runs for an entire week. It reshapes how the household eats, how it cooks, how it shops. The household’s full culinary life must be reconstructed around the absence of chametz for seven days.
The duration also means the prohibition cannot be forgotten or treated as a momentary inconvenience. Seven days of matzah establishes the Exodus memory as a structural feature of life, not a single evening’s commemoration. The Seder night is the narrative climax, but the chametz prohibition grounds the entire week in the physical memory of Egypt’s departure. You cannot eat chametz and simultaneously remember that you left Egypt in such haste that your bread did not have time to rise.
Chametz as the Five Grains — What the Prohibition Covers
The prohibition covers chametz derived from the five grains: wheat, barley, oats, spelt, and rye. These are the grains from which matzah can also be made. The distinction is in the preparation: matzah must be made from grain-water dough baked within eighteen minutes of mixing, before leavening can begin. Chametz is any product from these grains in which the leavening process has proceeded beyond that threshold. This means not only bread but beer, whiskey (grain-based), most cereals, pasta, and any product using these grains as a leavening ingredient.
The rabbinic laws around chametz are among the strictest in halacha. Unlike other prohibited foods — where a small amount mixed into a larger quantity may be nullified (batul b’shishim) — chametz is never nullified: even a minute quantity of chametz in a food renders the entire food forbidden on Passover. This principle (chametz b’masheh’u) reflects the special stringency of the chametz prohibition and the centrality of the Passover observance to Jewish identity. Exodus 12:19: “For seven days no leaven is to be found in your houses.” The verse sets a standard of absolute absence, not approximate reduction.
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