Nothing met with fire survives unchanged. Fire must be lit, dependent upon a source. And fire begins at times from just a spark. Fire spreads uncontrollably. But most notably, perhaps, fire depends, for all these things, on an unassuming fuel.
Fire requires oxygen, air.
The ordinary, the every day, the setting for the things that fire consumes. In a vacuum, fire is void. Now the Spirit cannot be at all extinguished. The Spirit is God Eternal. But Life in the Spirit is equally effective only when lived out in practice.