The ancient Zoroastrians, the first monotheist paid reference to Fire. The Upanishads said the supreme spirit is seen in the glow of fire and the radiance of the Sun. The Sun has always been the visible product of an unmanifest invisible intelligence. The glow of fire and the light of the Sun is the closest we can come to witnessing the spirit of life. We as humans have the 4 elements within us, we have our body the earth, our mind the wind, our emotions and body fluids the waters, and finally our inner will and cultivate the fire within. If we can manage to ignite our inner fire our spiritual flame it will purify the more gross elements of earth and water. Air is a mediating force between the elements and allows them to intermingle. The spirit is the 5th most subtle element, and we reach the ether through fire. That is why John the Baptist who symbolizes the baptism of Water says the one who comes after me baptizes with fire and the holy spirit.
Inner Mysteries 