Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 122
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 122, with English translation by Maimonides (Rambam).
שלא לשבור עצם בפסח שני, שנאמר (שמות יב, מו): "ועצם לא תשברו בו".
Not to break any of the bones of the Second Paschal sacrifice, as [Numbers 9:12] states: "Neither shall you break a bone of it."