1. Anything that exists has an explanation of its existence either in the necessity of its own nature or an external cause
2. If the universe has an explanation for its existence, that explanation is God.
3. The universe exists.
4. Therefore, the universe has an explanation of its existence. (from 1, 3)
5. Therefore, the explanation of the existence of the universe is God. (from 2, 4)
The argument is similar to the Kalam but has more premises and involves a necessary being and contingent things.
Premise 1: Two types of things exist: things that exist as a necessity of their own nature and contingent things. (contingent means something outside of itself that caused its existence)
If you read this, you are a contingent being, and you have an explanation for your existence: they're called parents. There is an explanation for your parents' existence: it's their grandparents. So, the cause of their existence is their great-grandparents.
The concept of a necessary being was difficult for me to understand. Some people believe that abstract numbers, mathematical sets, and operations are necessary. I have no problem with this, but it doesn't seem they can create anything other than a severe migraine.
Some intelligent people claim the universe doesn't need an explanation (perhaps not as smart as they think). Wow, this throws science out the window, and science does not give me a migraine. I enjoy learning about cosmology and hope scientists continue to gain a deeper understanding of the beginning.
Premise 2: If the universe has an explanation, that explanation is God.
God is a necessary being. Is there a more plausible premise than this one? Again, if you don't like the word God, you can say a timeless, beginningless, spaceless, immaterial being with a very powerful mind.
I am in no way saying this proves the Christian God. However, considering the beginning of Genesis, it is a likely candidate. Remember, before the universe began, there was no such thing as space-time or matter.
Premise 3: The universe exists.
So far, I haven't heard an objection to this premise, but I won't be surprised if I do. If someone holds this belief, it's okay with me, but I wouldn't bring it up during a job interview.
Premise 4: Therefore, the universe has an explanation of its existence, and that explanation is God.
Conclusion: Therefore, the explanation of the existence of the universe is God.
Therefore, Premises 1 and 3 infer the universe has an explanation.
Therefore, premises 2 and 4 infer that the cause of the universe is God.
The premises of the argument are more plausible than its detractors, and they infer the conclusion. Is it air-tight proof: no, but the argument is sound.
William Lane Craig
For more complicated arguments
https://plato.stanford.edu/entries/cosmological-argument/#BigBaosmOrig
https://www.divorcecare.org/groups/237245