Seven Days of Unleavened Bread and the Five Grains That Leaven

"Seven days you shall eat unleavened bread" (Exodus 12:15). I might hear that any unleavened bread is implied; Scripture teaches, "You shall not eat leavened bread with it" (Deuteronomy 16:3) - I have spoken only of a thing that can come to be unleavened or leavened. And these are the five species: wheat, barley, spelt, oats, and rye. Excluded are rice, millet, poppy, sesame, and legumes, which do not come to leavening but to spoilage. "Seven days you shall eat unleavened bread." I might hear that even a cooked dish is implied; Scripture teaches, "bread." "Seven days you shall eat unleavened bread" - together with the first festival day, or perhaps apart from the first festival day? Scripture teaches, "until the twenty-first day" (Exodus 12:18). And if "until the twenty-first day," one might exclude the time close to the twenty-first; Scripture teaches, "seven days you shall eat unleavened bread." To make the first day obligatory and the remaining days optional. Or perhaps to make the first day optional and the remaining days obligatory? Scripture teaches, "in the first month, on the fourteenth" - Scripture has fixed it as obligatory. One verse says, "seven days you shall eat unleavened bread," and one verse says, "six days you shall eat unleavened bread" (Deuteronomy 16:8). The seventh was included in the general rule and went out from the general rule to teach about the whole rule: just as the seventh is optional, so all of them are optional. If so, just as the seventh is optional, so the first night should be optional; Scripture teaches, "in the first month, on the fourteenth," and so forth - Scripture has fixed it as obligatory.