The idea of God being a consuming fire is found in Deuteronomy 4:23-25 and 9:3, and is reiterated in Hebrews. The idea is that because God is holy, nothing unholy (unrighteous) can be in His presence and is burned up. If you were face to face with a being such as this, somehow in the presence of one as described, you would throw down your idols, trinkets, and desires very quickly-maybe quicker than they could be burned up. If that’s true, it means God is very real, more real than what you are able to see using eyesight. Invisible doesn’t equal nonexistent.