If you were to place a dried out leaf into the presence of fire, you would notice that the fire would not hesitate to consume the leaf in a matter of seconds. The fire must consume the leaf because of its very nature. Even if the fire didn't want to dispose of the leaf, it wouldn't matter, it still must consume it because their natures are diametrically opposed to one another.
As Deuteronnomy 4 v 24, Hebrews 12 v 29 also describes God as a consuming fire. By His very nature, God must consume anything and everything that opposes His nature. We must put on the Lord Jesus Christ, or we will be consumed by the ever-pure burning holiness of the King of Kings