The Festival Day Guarded Against Labor and Rest Prohibitions

"And you shall guard this day throughout your generations" (Exodus 12:17). Why is this said? Has it not already been said, "No work shall be done on them"? From that I would know only matters that fall under the category of labor; matters that fall under the category of rest [shevut, rabbinically restricted activity], from where do I learn them? Scripture says, "And you shall guard," to include matters that fall under rest. And even the intermediate days of the festival should be forbidden under rest. And logic supports this: since the first festival day and the last are called a holy convocation, and the intermediate days of the festival are also called a holy convocation, then if you have learned about the first festival day [and the last] that, being called a holy convocation, they are forbidden under rest, is it not logical that the intermediate days of the festival, being called a holy convocation, are also forbidden under rest? Scripture therefore says, "On the first day a solemn rest and on the eighth day a solemn rest" (Leviticus 23:39). "In the first month, on the fourteenth" and so on (Exodus 12:18). Scripture established it as an obligation. "Until the twenty-first day of the month." Why is this said? Because it says, "Seven days you shall eat unleavened bread" (above, verse 15), from which I would know only the days; the nights, from where? Scripture says, "Until the twenty-first day," to include the nights.