The only evidence of who or what God is is revealed to us in His Word and in His world. From the clues in scripture and from the evidence demonstrated in Jesus, we assume that God exists beyond the 10 space-time dimensions that we know to exist.
Flatlanders. (going to need illustrations)
Imagine that you are a two-dimensional being. Your entire existence is composed of being a square on a plane. Everything you know is a square, all your friends are squares, the only thing that your worldview permits you to recognize is what you can perceive, which is other squares. Now imagine trying to explain to the square, what it means to be a cube.
The sage square says that he has discovered an entire new dimension, one that spreads out the mere existence of a square to that of a cube. This third dimension spreads out a square across more than its mere two-dimensional existence. Even though the square does not have the vocabulary or perspective to explain it, there is height which makes the cube so much more than the square can perceive. That third dimension increases what the cube is, even though on the surface it may appear to be just another square to the flatlander square.
Similarly, Einstein declared that Time “spreads everything out so it doesn’t all happen at once.”
Just as height spreads out the cube, so it even though it exists as a square, it does not remain locked in that dimension. The sum of its reality is expanded.
Now imagine something that exists in 5th-dimensional space. I had stated earlier that our minds are not able to perceive it. We just don’t have a vocabulary to express what something looks like or how it behaves in 5th-dimensional space. The only reason we know that 5th-dimensional space exists is because of mathematics. With mathematical equations it can be demonstrated that a ball can be turned inside-out in 5th-dimensional space without breaking the surface of it. Try to visualize the possibility of that and you will soon discover that you cannot. It exists beyond what you are able to perceive in your 4-dimensional existence. Just as the following 3-dimensional object can change it’s orientation without moving in 2-dimensional space, but by moving 3-dimensionally (twisting square prism).
So since we now know that our universe exists in a 10-dimensional space-time continuum, and we are told that God existed outside of that 10-dimensional space, how can man fully comprehend all that is God?