שמות, פרק י״ג, פסוק ז׳

The festival of Passover ushers in a complete physical and spiritual transformation, where familiar daily bread is replaced by matzah and all traces of leaven are banished from the environment. The directive to eat matzah establishes a general standard for the holiday [הכתב והקבלה]. The primary approach among commentators is that consuming matzah throughout the seven days is not an absolute obligation, but rather a conditional one: if a person chooses to eat bread during this time, it must be matzah [הכתב והקבלה, ביאור שטיינזלץ]. This standard applies to all members of the household [העמק דבר]. Furthermore, the positive command to eat matzah inherently carries a hidden prohibition against consuming leaven [פרדס יוסף].

The restriction on leaven begins even before the festival officially commences, taking effect from the afternoon of the day preceding Passover [רבנו בחיי, תורה תמימה, מלבי״ם]. This expanded timeframe is also understood to encompass the obligation to observe a second festival day in the diaspora [רבנו בחיי]. The Torah demands more than just eating matzah; it requires a total distancing from leaven [קאסוטו]. This complete absence of leaven from the home is not merely a legal technicality, but a deliberate educational strategy. Altering the home environment sparks wonder in children, prompting them to ask questions and firmly rooting the memory of the Exodus in their hearts [העמק דבר].

The prohibition against seeing leaven is strictly tied to personal ownership [הכתב והקבלה, תורה תמימה]. Therefore, a person is permitted to see leaven belonging to a non-Jew or leaven that has been dedicated to the Temple [תורה תמימה]. Because leaven on Passover is legally forbidden for any benefit and is no longer considered the property of the Jew, the restriction specifically targets leaven that was owned before the holiday began [הכתב והקבלה]. This ban includes both regular leavened food and sourdough used as a rising agent, provided there is a minimum measurable amount [תורה תמימה, רלב״ג]. If a Jew retains ownership of leaven throughout the holiday, a strict penalty applies: the leaven remains permanently forbidden for any use or benefit even after Passover concludes, unlike a non-Jew's leaven, which becomes permitted again [תורה תמימה].

The requirement to clear leaven from one's borders extends beyond physical property lines to include any area, structure, or space under a person's authority [הכתב והקבלה]. Responsibility, rather than physical location, is the decisive factor. Consequently, leaven owned by a Jew but held as collateral by a non-Jew, a non-Jew's leaven placed in a Jew's home without the Jew assuming responsibility for it, or leaven buried under inaccessible rubble, are exempt from the prohibition [תורה תמימה]. Ultimately, purifying the entire territory from leaven is a fundamental condition for living in the land. It reflects a broader national responsibility, much like the obligation to ensure that even a stranger residing within the city gates rests from labor on the Sabbath and the Day of Atonement [אבן עזרא].