Levítico 23:7 Halajá: Mishneh Torah, Rest, Sefer HaChinukh & Mishneh Torah, Negative Mitzvot

These six days on which Scripture prohibited labor—being the first and seventh days of Passover, the first and eighth days of Sukkot, the day of Shavuot and the first day of the seventh month (Rosh Hashanah)—are called holidays (yamim tovim). The [degree of] cessation of work is equal in all of them, in that all work is prohibited except for labor that is for the sake of eating—as it is stated (Exodus 12:16), "only anything that is eaten by any person."

Anyone who rests from work of labor on one of them has surely fulfilled a positive commandment; as it is surely stated about them (Leviticus 23:24), "a day of rest (shabbaton)" -meaning to say, "Rest!" And anyone who does work on one of them which is not for the sake of eating—such as [if] he built or demolished or wove or that which is similar to these—has surely negated a positive commandment and violated a negative commandment, as it is stated (Exodus 12:17), "no work shall be done on them." And if one did it [in front of] witnesses and with a warning, he is lashed from Torah writ.

In the same way that there is an obligation to honor the Sabbath and to delight in it, so too [is it with] the holidays. As it is stated (Isaiah 58:13) "to sanctify the honored Lord"; and it is stated about all of the holidays (Leviticus 23:7), "a time of holiness." And we have already explained [this] honoring and delighting in the laws of the Shabbat. It is therefore fit for a person to refrain from having a meal on the eve of holidays from the time of the afternoon prayer, like on the eve of Shabbat. As this thing is part of [its] honor. And anyone who disgraces the festivals is as if he was associated with idolatry.