Leviticus 6:8-13

Then the LORD spoke to Moses, saying, “Command Aaron and his sons, saying, ‘This is the law of the burnt offering: the burnt offering shall remain on the hearth that is on the altar all night until morning and the fire is to be kept burning on the altar. The priest is to put on his linen robe, with his linen undergarments next to his body. Then he shall take up the ashes of the burnt offering which the fire has consumed on the altar and put them beside the altar. Then he shall take off his garments and put on something else, and take the ashes outside the camp to a (ceremonially) clean place. The fire on the altar shall be kept burning; it shall not [be allowed to] go out. The priest shall burn wood on it every morning, and he shall arrange the burnt offering on it and offer the fat portions of the peace offerings up in smoke on it. The fire shall be burning continually on the altar; it shall not [be allowed to] go out.