The universe and everything in it obeys the laws of cause and effect and exists within space time and matter.
There is no matter that can exist without holding space at a specific time.
And inline with the laws of cause and effect everything has a beginning and an end.
Since the universe also follows these fundamental laws it is clear there was a beginning and will eventually come to an end.
But since the universe is the sum total of all in existence that which created it must exist outside the realm of our perception of existence and does not follow these rules.
This leads us to God who being the Creator must not be affected by the laws of cause and effect and fundamental laws of existence; as matter in a specific place at a specific time.
Since God is not affected by these laws he can exist without being in a defined position in time or space. And can exist in all places at the same time at all times and therefore has no defined position in space time and is not detectable as physical matter.
He has no beginning or end and exists
in all places at all times.