Leviticus 6:10-20

10 that the priest hath put on his long robe of fine linen, and his fine linen trousers he doth put on his flesh, and hath lifted up the ashes which the fire consumeth with the burnt-offering on the altar, and hath put them near the altar;
11 and he hath stripped off his garments, and hath put on other garments, and hath brought out the ashes unto the outside of the camp, unto a clean place.
12 `And the fire on the altar is burning on it, it is not quenched, and the priest hath burned on it wood morning by morning, and hath arranged on it the burnt-offering, and hath made perfume on it [with] the fat of the peace-offerings;
13 fire is continually burning on the altar, it is not quenched.
14 `And this [is] a law of the present: sons of Aaron have brought it near before Jehovah unto the front of the altar,
15 and [one] hath lifted up of it with his hand from the flour of the present, and from its oil, and all the frankincense which [is] on the present, and hath made perfume on the altar, sweet fragrance -- its memorial to Jehovah.
16 `And the remnant of it do Aaron and his sons eat; [with] unleavened things it is eaten, in the holy place, in the court of the tent of meeting they do eat it.
17 It is not baken [with] any thing fermented, their portion I have given it, out of My fire-offerings; it [is] most holy, like the sin-offering, and like the guilt-offering.
18 Every male among the sons of Aaron doth eat it -- a statute age-during to your generations, out of the fire-offerings of Jehovah: all that cometh against them is holy.'
19 And Jehovah speaketh unto Moses, saying,
20 `This [is] an offering of Aaron and of his sons, which they bring near to Jehovah in the day of his being anointed; a tenth of the ephah of flour [for] a continual present, half of it in the morning, and half of it in the evening;