If God Created the Universe then Who Created God?

This is a question I've heard many times in the past years, and have often wondered myself how Christians can answer. I had for a while thought that both Christianity and atheism boiled down to one basic belief that something had to exist before everything. This thing was either God in the Christian view, or an infinitely tiny and dense particle of mass that exploded into life in the atheist view. The conflict then becomes which scenario is more plausible? But now that I've done some reading I've learned that there is more to the issue than I first thought.

The question "Who made God?" has actually been around for some time. Bertrand Russel, a well known atheist concluded, "If everything must have a cause, then God must have a cause." Stephen Hawking begs the same question. Atheists have been attempting to explain away the necessity of God in the creation of the world as long as atheism has existed. The Steady State Theory suggests that the earth has always existed in eternity past, where as the Oscillatory model posits that the universe has been expanding and contracting continuously into eternity past. Some even believe that the universe came into existence uncaused out of nothing.

Many issues arise with this understanding of the universe, and from scientific discovery we have uncovered a number of things that refute these claims. The observations that the universe is expanding points to some beginning of the earth such as in the Big Bang theory. We also know that the universe cannot exist in eternity past because we know that an actual infinite amount of time is not possible. If you can imagine that if the universe existed in eternity past, then an infinite number of events must have existed prior to the present. But if an infinite number of past events have taken place, it is impossible to ever arrive at the present.

The second law of thermodynamics tells us that things cannot spontaneously come into existence out of nothing. In fact, this was even refuted by one of the most noted atheists, David Hume. What we can say is that whatever begins to exist must have a cause. This is consistent with what we know about our universe. If everything that begins must have a cause and we know that the universe began, then what caused the universe? Some atheists might posit that the universe caused itself into existence, but we know that the cause of any one thing cannot be the thing itself. We also know that an actually infinite number of events cannot exist, and as such there cannot be an infinite regress of causes going into eternity past. The logical conclusion is that some thing that is uncaused and eternal must be the reason behind the universe. Something that trancends time and space. But then what is this eternal and uncaused entity? In Christian understanding, this is God.

I think William Lane Craig sums this up well in a conversation he had with a student when asked "If God created the universe then who created God?" To which he replied, "God didn't come from anywhere. He has eternal and has always existed. So he doesn't need a cause. But now let me ask you something. The universe has not always existed but had a beginning. So where did the universe come from?"

It then comes down to a an understanding that God is, in fact, the best explanation as to the beginning of the universe.