Leviticus 6:13

This is the gift of Aaron and of his sons, which they shall offer to the Lord in the day in which thou shalt anoint him; the tenth of an ephah of fine flour for a sacrifice continually, the half of it in the morning, and the half of it in the evening.

And the fire shall always burn on the altar; it shall not be extinguished.

Fire shall be kept burning on the altar continually; it shall not go out.