הלכה על שבת 49:6

That is that He commanded us to rest on the first day of Pesach. And that is His, may He be exalted, saying, "And on the first day, a sacred occasion" (Exodus 12:16). And the explanation (Rosh Hashanah 32a) came [to say] - "Sanctify it" - that is, that you should not do any work on it except that which is specific for eating alone, as is explained in Scripture. And their language already appeared (Sefer Hamitzvot, Positive Commandments 90), "This term, Shabbaton, is a positive commandment" (Shabbat 25b). This means to say, that every holiday about which God said, Shabbaton, is as if He said, "Rest," or "You shall rest" - and these are all commands to rest. God's days of rest are called sacred occasions, meaning to say, holidays. And their saying - "a holiday is a positive commandment and a negative commandment" - has already come in explanation in many places. This means that the negation of work on a holiday is a positive commandment; and that [not] doing certain work is a negative commandment. And hence one one who does certain work on it has transgressed a positive commandment and a negative commandment. And the regulations of this commandment - meaning resting - have already been explained in Tractate [Beitzah]. (See Parashat Emor; Mishneh Torah, Rest on a Holiday 1.)