The foundation of the Passover festival blends meticulous physical action with profound spiritual significance that spans an entire human lifetime. The framework for this observance centers on the consumption of unleavened bread for seven days, serving as a historical anchor to the Exodus from Egypt. The Israelites consumed unleavened bread not only on the night of their departure but for a full seven days, up until the drowning of the Egyptians in the Red Sea. Because God led them by His cloud day and night in constant haste, there was simply no time for their dough to rise [אבן עזרא]. Beyond this historical memory, the seven-day period holds a deep spiritual resonance. Seven days symbolize a complete human lifespan of seventy years. Throughout life, a person is challenged to distance themselves from leaven, which represents the evil inclination and base desires, and instead cling to unleavened bread, embodying purity, humility, and Divine mercy [אברבנאל, רקנאטי].
While the instruction to eat unleavened bread spans a full week, the primary approach among commentators is that this consumption is not mandatory for the entire duration. The absolute obligation to eat unleavened bread applies strictly to the first night of Passover. During the remaining six days, it is optional; a person may eat fruits, meat, or even fast, provided they do not consume any leaven. Nevertheless, choosing to eat unleavened bread during these remaining days still fulfills a Commandment and draws down spiritual merit [אור החיים]. To properly fulfill this duty, the unleavened bread must be baked from a grain that possesses the natural capacity to rise, such as wheat or barley. Only a substance capable of becoming leaven can be transformed into the required unleavened bread [מלבי״ם, תורה תמימה].
Before the festival begins, a crucial process of removal takes place. The directive to eliminate leaven on the initial day mentioned actually refers to the day prior to the festival, the eve of Passover, as biblical language frequently uses the concept of first to indicate that which precedes [רש״י, שד״ל, כתב והקבלה]. This obligation does not commence at the break of dawn, but rather takes effect from midday onward [אבן עזרא, מלבי״ם]. The required method of removal is highly specific, focusing on nullification and cessation rather than merely burning or destroying. The primary removal mandated by the Torah occurs within the mind. A person must mentally nullify their leaven, declaring it entirely useless and viewing it as nothing more than the dust of the earth. However, any leaven that is visible and known must still be physically removed [כתב והקבלה, תורה תמימה]. The Torah places equal severity on both the sourdough starter used to make dough rise and the final leavened product itself, applying the exact same standards for their removal and the consequences of their consumption [העמק דבר, תורה תמימה].
Consuming leaven during the festival carries the severe consequence of spiritual excision. This punishment is reserved strictly for those who act intentionally, with full awareness and a settled mind, entirely exempting anyone who consumes leaven by accident or under coercion [רש״י, תורה תמימה]. The consequence applies equally to someone who drinks a leavened mixture, as drinking also provides a satisfying, settling effect on the soul [תורה תמימה]. The nature of this excision is both spiritual and physical, severing the soul from its Divine root and from the broader community of Israel, regardless of where the person may reside [רש״י, אברבנאל]. The continuous timeframe from the eve of the holiday through the seventh day reinforces that the obligation to remove leaven and the prohibition against eating it remain unbroken [כתב והקבלה]. Furthermore, this specific span of days highlights the inescapable nature of the consequence; even a very elderly person, who has already surpassed the typical age associated with the punishment of a shortened life, will still face this consequence during these seven days if they deliberately consume leaven [פני דוד].