To our minds, the entire problem of the “first cause” is a paradox. The spontaneous existence of the universe, without God, makes no sense, yet we also can’t make sense of God’s own origins either.
At first glance, it appears to be a stalemate between the theistic (belief in God) and atheistic viewpoints. However, let’s look more closely. If we assume that God created the universe, then we leave open the possibility that God, being infinitely wiser than ourselves, can possibly understand His own origins and resolve the paradox for us.
If we assume the universe just exists on its own, then we run into a more serious difficulty, because we cannot, ourselves, explain our origins. This limitation is not based on the current state of science or technology. Whatever we do to explain the origins of the universe (for example, finding some physical cause to the Big Bang) within the framework of human knowledge simply pushes back the causal chain one more link.
It’s like a detective looking at a complicated crime scene, or or an anthropologist trying to understand the engineering techniques at Stonehenge. In both cases, after a substantial amount of unsuccessful effort, one might get the sense that “I can’t figure this out”, and then even “maybe there isn’t enough information left for anyone to figure this out”. Nonetheless, in both cases, one would cling to the view that “someone out there must know (or have known) how this thing got here”. In other words, it is less troubling to assume God as the answer to the paradox (and let Him figure out His origins) than to accept that things happen for no reason at all.
In this sense, the existence of the universe still weighs in, on net, as evidence in favor of the existence of God. Personally, I find the argument for God’s existence arising from consciousness to be more powerful. Together, the arguments from the “first cause” and from consciousness provide not a complete explanation of reality but a two-pronged attack on naturalism, the idea that the laws of physics ultimately explain everything. If one concludes that the universe cannot explain its own existence, and that human consciousness as we directly observe and experience it in ourselves cannot have arisen from unconscious matter through unconscious laws, then God is the obvious candidate. It doesn’t have to be the Christian God necessarily, but something supernatural is needed, and once that conclusion is reached, testimonies like the Christian Gospels appear in a different light. Rather than being rejected out of hand because they are inconsistent with a naturalistic worldview, they can be taken as one of several possible candidates for revealing some characteristics of “the supernatural”. (And looked at on this basis, they compare very well to the alternatives.)