Fixing the Hour When Matzah Begins and Leaven Ends

"In the first month" (Exodus 12:18) - one might think during the whole of it; therefore Scripture says "on the fourteenth." Or "on the fourteenth" - one might think in the morning; therefore Scripture says "day." Or "day" - one might think from two hours in; therefore Scripture says "at evening." Just as "at evening" means after the day has turned, so when it says "day" it means after the day has turned, from the sixth hour and onward. One might think you are obligated in matzah on the fourteenth; therefore Scripture says "upon it" (Deuteronomy 16:3) - upon it [the Passover offering] you are obligated in matzah, but you are not obligated in matzah on the fourteenth. If so, why is "on the fourteenth" said? If it does not apply to the eating of matzah, apply it to the removal of leaven. ["Until the twenty-first day of the month" - one might think you are obligated in matzah all seven days; therefore Scripture says "upon it" - upon it you are obligated in matzah, but you are not obligated in matzah all seven days. I know this only when the Temple stands; from where when the Temple does not stand? Scripture says "in the evening you shall eat unleavened bread" - Scripture established it as an obligation. I know this only in the Land; from where outside the Land? Scripture says "in all your dwellings you shall eat unleavened bread." If we are in the end to include all these, what does "until the twenty-first day of the month" teach? If it does not apply to what precedes it, apply it to what follows it.] "Seven days no leaven shall be found in your houses" - I know only days; from where nights? Scripture says "until the twenty-first day of the month at evening no leaven shall be found in your houses."