Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 324
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 324, with English translation by Maimonides (Rambam).
שלא לעשות מלאכה בשביעי של פסח, שנאמר "כל מלאכה, לא ייעשה בהם" (שמות יב,טז).
Not to work on the seventh day of Pesach, as [Leviticus 23:8] states concerning it: "Do not do any servile work on these [days]."