"These have power to shut heaven" (Rev. 11:6)
I realized altho' people make much ado about the power of the two witnesses -- and they are very real -- you can look back at verse 3 and see the power has been given them by God Himself. It's not as if THEY were powerful beings who came before God and offered themselves to God for His service! GOD gave them that power, good grief!
I would find it ludicrous if any of the animated creatures I wrote fictional stories about came before me and bragged to me of their virtues -- I had, after all, thought them up and written them into existence -- no human creature can really think he is embued with power somehow on his own, and it's completely separate of the Creator's fashioning him to make him that way! As a matter of fact, much less than the power to work miracles, even the very ability to take the very next breath, for the brain waves to move and electrical impulses to vibrate through nerves -- GOD CONTROLS THAT.