Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 121
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 121, with English translation by Maimonides (Rambam).
שלא לשבור עצם בפסח, שנאמר (שמות יב, מו): "ועצם לא תשברו בו".
Not to break any of the bones of the Paschal sacrifice, as [Exodus 12:46] states: "Neither shall you break a bone of it."