If ever there was a time when absolutely nothing existed, there would still be nothing, for nothing cannot cause any thing to exist. All effects must have a cause, as even the king of the skeptics admitted, David Hume. To say that something could arise without a cause is to admit absurdity, for one of the most basic principles of reason is that no effect can come to exist without a cause. No one has ever demonstrated an effect without a cause, not even in the shadowy, partially-known world of theoretical physics commonly referred to as quantum physics. Most quantum-laced responses can be summed up by the adage ‘they did not explain it, they quantumed it.” Some have given absurd answers similar to saying that the universe does not need a cause since it came from fluctuations in the quantum vacuum. This is nonsense, for if we can speak of fluctuations and vacuums such that our sentences have subjects and predicates, attempting to meaningfully predicate something to the quantum world, we have not started with nothing, but something. What caused the fluctuations? What was the situation that defined the quantum vacuum? These are things, and if ever there was a time when absolutely nothing existed, there would still be nothing, since nothing cannot cause any thing to come to exist.
Therefore something has always existed. Many have tried to say this something was matter, but matter is subject to the laws of thermodynamics which tell us that the universe would have died a heat death eons ago. Further, all instances we have observed of material things show us that they are limited. Limited things have potential that has not been actualized, and are therefore composed of potential and actual. All composed things have been caused to be by a prior cause. No one has ever demonstrated a composition that came to be on its own, and with the cumulative experience of all mankind, the burden of proof is therefore on the skeptic to demonstrate that composition can come to be without a cause.
So the thing that is the cause of what has come into existence must be non-material, uncomposed, and without a prior cause. This we call God.