"In the beginning … what? Genesis 1:1
says “In the beginning God created the heavens and the earth”, but why
think that’s true?
First, nothing comes into being without a cause, a
basic principle of science and rationality. Everything we see that
started to be has some sort of cause. 
But we also know that the universe
itself had a beginning. The laws of thermodynamics powerfully imply
that the universe had a beginning. And an infinite regress of secondary
causes can’t even exist, because it can be shown mathematically
that this would lead to absurdities! But that means the universe itself
had a cause.
Q: But what could cause the universe?
A: The universe is all of
space-time-matter reality, so the cause can’t be bound by those things.
And it must be powerful to cause the universe!
The simplest solution is
an eternal, non-material, uncaused cause.
Q: But how to get a temporal
effect from an eternal cause?
A: That cause must have freely chosen to create, so it must be a personal
cause.
So the simplest cause for the universe is a single, powerful,
personal, eternal, immaterial, uncaused cause—it sounds a lot like God." CMI