Fire is a source of energy. Everything that moves in the physical world uses energy, and energy is produced through burning. In order for our service to be full of energy, our service must pass through the fire on the altar. This is not strange fire, which is of man and of the earth. Rather, this is holy fire. This fire is of God and of heaven. Our service must come out of the burning of God’s fire. This fire should be the energy, the driving force, the impulse within us. Then our service will be out of God, not out of ourselves.
Those who have a desire to serve God must remember that our God is a consuming fire (Hebrews 12:29). When God comes to the earth, fire comes to the earth. When God enters into man, fire enters into man and burns in him. The degree of burning may be different, but every believer experiences being burned. God is not cold. He is fire that energizes and burns. Those who draw near to God experience the burning. God is a consuming fire, and His eyes are like a flame of fire (Revelation 1:14). Whoever touches Him will be burned. (The Service for Building Up the House of God, ch. 2, by Witness Lee)