It simply means denying God's existence is not only absurb, but totally illogical.
If there is a possibility that the universe exists on its own, how is it out of question that there is really an omnipotent Being who is the sole originator of every single atom that there is?
Who created God? You say.
And, who created the universe?
Who called the so-called Big Bang into action?
What about singularity?
You see! We may search and search for answers, but all this boils down to the same fact - In the beginning, God created!
What about Him? Simple. He has always been in existence - since forever, since eternal past!
How is it possible? Because He's God!