It was much easier to keep it burning. Man learned that fire can snugly sleep beneath ashes and arise glowing when blown in flames. Habit forms tradition. The hearth fire and later the temple fire became an ever-burning fire. Tradition becomes sacred.
Sacredness demands ritual.
Ritual becomes elaborate. Once sanctified and ritualized, even when well out-dated and fossilized, a tradition cannot be easily abandoned by conservatives. Match sticks and gas and electric lighters have put out the hearth fire, and yet I know in Iran there are still old ladies, Zoroastrians and Muslims, whose hearth fire is never extinguished. Fire has served as the altar, the illuminating light, for many religions. Fire, in form of candid candle, lighted lamp, burning incense, and blazing wood, still adorns prayer niches, rooms and halls all over the world.