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When Adam was created, he did not have to work hard and struggle to make a living. However, this changed when he sinned by eating from the tree of knowledge. God expelled him from the Garden of Eden, and the land was cursed. This meant that people would have to work hard to survive. (See Genesis 3:17-19.) This hard work would gradually rectify the sin. However, subjugation to work puts us at risk of drowning in the material world and forgetting our lofty souls. Therefore, God gave us holy days during which we rise above the sin and its curse. The elevation and illumination of these days can then guide us on the weekdays as well.
The sanctity of Shabbat is permanent and enduring. Ever since God created the world in six days and rested on the seventh, this seventh day has been Shabbat. In contrast, the sanctity of the festivals depends upon the Jewish people. This dependency is twofold. First, the unique idea of each festival was revealed through the Jewish people. On Passover, God redeemed the Israelites from Egypt; on Shavuot, God gave them the Torah, and on Sukkot, we remember the special divine providence they experienced. On Rosh Ha-shana, the Jews are representatives of the entire creation, crowning God as ruler of the universe, extending blessing upon all. Second, the timing of the festivals depends upon the Jewish months, which were sanctified by the Jewish people (section 1 above).
Shabbat has greater sanctity than the festivals, and desecrating it is a graver sin. This is because Shabbat is when we ascend to a very high level of faith, submitting ourselves to divine providence by refraining from melakha. In contrast, the festivals reveal the greatness of the Jewish people. For this reason, the mitzva to be happy and enjoy festive meals and fine clothing is greater on the festivals than on Shabbat. Melakha necessary to enable the preparation of the festive meals in the home kitchen is permitted on Yom Tov (section 12 below).
