And the 30th mitzvah is that the priests are commanded to remove the ashes from the altar each day. This is called, "terumas hadeshen."

The source of this commandment is G‑d's statement1 (exalted be He), "The priest shall then put on his linen garment, and put linen pants on his body ... and he shall remove the ashes."

The details of this mitzvah have been explained in tractate Tamid2 and in tractate Kippurim.3