In order to be the cause of time, God must necessarily be able to exist in a timeless state. It follows from this that God must be timeless, beginningless, and uncaused.
What Caused the Universe?
Just as a woman cannot give birth to herself, so nature cannot have brought itself into existence. If the origin and foundation of the physical world cannot be natural, then it must be something that is not-natural.
Did Time have a Beginning? -- My First Brush with Infinity
The beginning of time isn’t something people often ponder when sipping an Americano in a coffee shop, but they should … the philosophical implications are massive.