"Our God is a Consuming Fire" - What Does this Mean?

​“For our God is a consuming fire” (Hebrews 12:28-29 ESV)
 
The author of Hebrews is quoting from Deuteronomy 4:24.  The context there is that Moses was warning Israel not to worship anything except God.  He then says, "For the Lord your God is a consuming fire, a jealous God" (Deut 4:24 ESV).  By depicting God as a consuming fire, Moses is basically warning them that God can destroy them (picture the destruction caused by wild fires... that's the kind of image to have in mind here).

​Later on in Deuteronomy, Moses uses identical imagery, but this time to tell them what God will do to their enemies: "Know therefore today that he who goes over before you as a consuming fire is the LORD your God. He will destroy them and subdue them before you..." (Deuteronomy 9:3 ESV). Again, the image is that of destruction.
 
Finally, the author of Hebrews brings this imagery of God's destructive power to the mind of his readers to seal his exhortation that they are to worship with reverence and awe: "Therefore let us be grateful for receiving a kingdom that cannot be shaken, and thus let us offer to God acceptable worship, with reverence and awe, for our God is a consuming fire" (Hebrews 12:28-29 ESV).
 
So, the description of God as a consuming fire is a warning that we are not to mess with God. He can destroy us in an instant. Furthermore, He can also destroy our enemies in an instant. Knowing God has such power is to produce in us a reverent fear and awe.