Fire

                                                        Hebrews 12:25-29
See to it that you do not refuse Him who is speaking. For if those did not escape when they refused him who warned them on earth, much less will we escape who turn away from Him who warns from heaven.
And His voice shook the earth then, but now He has promised, saying, "YET once more I WILL SHAKE not only the earth, BUT ALSO the heaven."
This expression, "Yet once more," denotes the removing of those things which can be shaken, as of created things, so that those things which cannot be shaken may remain.
Therefore, since we receive a kingdom which cannot be shaken, let us show gratitude, by which we may offer to God an acceptable service with reverence and awe;
for our God is a consuming fire. 

                                                                  2 Peter 3:7
But by His word the present heavens and earth are being reserved for fire, kept for the day of judgment and destruction of ungodly men.