S. Michael Houdmann, CEO of GotQuestions.org writes:
"We know that from nothing, nothing comes. So, if there were ever a time when there was absolutely nothing in existence, then nothing would have ever come into existence. But things do exist. Therefore, since there could never have been absolutely nothing, something had to have always been in existence. That ever-existing thing is what we call God. God is the uncaused Being that caused everything else to come into existence. God is the uncreated Creator who created the universe and everything in it."
Read more: http://www.gotquestions.org/who-created-God.html
"Our Lord and God, You are worthy to receive glory and honor and power, because You have created all things, and because of Your will they exist and were created." - Rev 4:11