The Bible has a collection of images that it uses for the Holy Spirit -- and fire is one of the main ones. This fire is not a destructive fire, but a purifying fire, a holy fire. It is light in the darkness. It is the light that shines before men, the lamp on the lamp stand. It is the smolder that clings to the wick that is not snuffed out yet. It is the burning in the bosom as we hear the words of Christ. It is the flame that we fan. It is one way that faith passes from us to the next person -- that they feel the warmth, see the light, and are drawn. It is part of how we encourage each other, and part of why there is so much power in fellowship. In isolation, we are candles in the dark. Together, we are a bonfire.
In one of the Greek myths, man is denied fire -- it is reserved for the gods -- and the man who steals the power of fire is dealt a stern punishment. On Pentecost, God takes the fire of His own Spirit, and sends it down to man: The tongues of fire light on all the believers so that the young men will see visions, the old men will dream dreams, and on all -- both sons and daughters -- the spirit is poured out. God does not try to deny man the power of God: He pours it out on us, to lift us up, and restore us, and kindle the divine Spirit in us. God is a gracious God.