Rambam - Sefer HaMitzvos: Positive Mitzvah 91: Positive Mitzvah 91

Positive Mitzvah 91: Burning the Leftovers
Leviticus 7:17 "But that which remains of the flesh of the sacrifice, on the third day, shall be burnt with fire"

A sacrifice offered to HaShem must be treated with care.

Parts of certain sacrifices are eaten by the priests and the people who brought them.

However, the Torah places a specific time limit on eating this meat.

The time limit depends on the type of sacrifice that was brought.

Leftover meat that was not eaten by this time is called Notar and may not be disposed of carelessly (see Negative Mitzvot 1 16-1 17). We must burn any leftover meat.

The ancient philosophers divided the world into four realms, each realm transcendental in a way beyond those that precede it: The inanimate --earth, rocks, water, etc., do not transcend their bounds in any way.
Flora transcends its bounds by growing. Fauna transcends its bounds by movement from place to place. And Man, how does he transcend his bounds? Man reaches outside of himself with words. With dialogue.
Man alone is capable of hearing his own self through the ears of another. Man alone is capable of transcending the very bounds of self.

From: Bringing Heaven Down to Earth by Tzvi Freeman - tzvif@aol.com