Leviticus 6:9-13

9Command Aaron and his sons, saying, This is the law of the burnt-offering: the burnt-offering shall be on the hearth upon the altar all night unto the morning; and the fire of the altar shall be kept burning thereon. 10And the priest shall put on his linen garment, and his linen breeches shall he put upon his flesh; and he shall take up the ashes whereto the fire hath consumed the burnt-offering on the altar, and he shall put them beside the altar. 11And he shall put off his garments, and put on other garments, and carry forth the ashes without the camp unto a clean place. 12And the fire upon the altar shall be kept burning thereon, it shall not go out; and the priest shall burn wood on it every morning: and he shall lay the burnt-offering in order upon it, and shall burn thereon the fat of the peace-offerings. 13Fire shall be kept burning upon the altar continually; it shall not go out.