God is a Spirit.  He is the HolySpirit.  -> physical beings cannot see spiritual things with their eyes -> God created the vast universe so He is bigger than what He created.<p>Seeing and living implies that a living physical human cannot see the HolySpirit.  <p>Jesus confirmed this to Nocodemus saying that the HolySpirit is not visible.  You only see the evidence of Him by that which He effects.<p>The one speaking to Moses is preincarnate Jesus whom neither Moses nor anyone living at that time could see because it was not yet time for the HolySpirit to reveal Himself to mankind InChrist Jesus.