Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 156
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 156, with English translation by Maimonides (Rambam).
שלא לעלות לחג בלא קרבן, שנאמר "ולא ייראו פניי, ריקם" (שמות כג,טו).
Not to make a festive pilgrimage without [bringing] a sacrifice, as [Exodus 23:15] states: "Do not appear before Me empty-handed."