Rabbi Aharon Halevi, writing in 14th century Spain, said: “By attending daily to the command of fire we may merit blessing in the matter of the fire that is within us. And what is this fire within, if not the life force of the person?”
So perhaps when we are told to keep the fire alight day and night, what we are really talking about is the human spirit. We are commanded to be a nation of priests, to take responsibility for our world, to be healers and, when necessary, to stand between life and death, as Aaron does. But we need to nurture ourselves.
Without a perpetual fire burning on the altar, all our prayers, all our attempts at forming relationships, all our holy work would cease. This fire on the altar of our hearts is the prerequisite for everything we do. Tzav directs us in how to look after our innermost fire. If it goes out, if we lose our sense of spirit, our sense of hope, then everything we do is meaningless.
The purpose of keeping the fire going in the Torah narrative is to be able to offer up sacrifices. The word for sacrifice in Hebrew is korban, and to bring a sacrifice is a verb from the root form, karav. Karav means to “come close”. We are talking here about how to come close to God, how to come close to each other, how to come close to ourselves.