We now enter a long series of mitzvos pertaining to the various holidays. First we have the obligation to refrain from acts of constructive labor on the first day of Passover, AKA Pesach. People typically say to “rest” on Shabbos and Festivals (Yom Tov), but that doesn’t mean just to take a nap. It means to refrain from creative activities that we call “melacha” (see Mitzvah #32).
The Torah called the day “mikra kodesh,” a holy gathering, from which we see that we are to sanctify the day. The same labors are prohibited on Festivals with the exception that we may prepare the food we need to eat (as seen in Exodus 12:16). The Talmud in Shabbos (24b) tells that the word “Shabbaton” (said in conjunction with the holidays in Leviticus 23:23 and 23:39) denotes a positive mitzvah to refrain from labor on these days.
The reason for this mitzvah is that Yom Tov should not be spent engaged in our usual activities. We shouldn’t be chopping wood, driving, writing or texting. We should spend the day thinking about God and the meaning of the holiday. In the case of Pesach, we are supposed to think about the great miracles that God wrought for us when He redeemed us from slavery in Egypt.
This mitzvah applies to both men and women in all times and places. It is discussed in the Talmud in the tractate of Beitza and in Makkos (21b-22a). It is codified in the Shulchan Aruch in Orach Chaim 495. This mitzvah is #159 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos and #25 of the 77 positive mitzvos that can be observed today in the Chofetz Chaim’s Sefer HaMitzvos HaKatzar.