by jimwalton » Mon Aug 14, 2017 4:56 pm
God's omnipresence has never been adequately defined. In the Old Testament is comes across more in the sense of "there is no place to which God does not have access." In the NT it comes across more like "God is everywhere at the same time," though both ideas occur in both testaments. We also know from the Bible that God's presence in places can seem to change in its intensity and quality, as in when "the presence of the Lord descended on the temple." Um, wasn't he already there if he is omnipresent? Yes, but now he's present in a different way. All of this is to say that there is an indistinct answer to what it means that God is everywhere.
But I'll still try to answer your question. "Heaven" is generally described as the home of God, though there's every reason to believe at this point it has no materiality, or at least a different kind of materiality (Jesus was material after his resurrection, but he could walk through our solid wood doors as if they weren't there). God is non-material; we have no idea about the materiality or spirituality of angels, cherubim, seraphim, etc., but if they are "material," they probably exist in the same kind of different materiality that Jesus does.
So where is God? He's everywhere, as you say. There is no place He is not, though His presence can be different in quality or intensity, so to speak, from place to place. He is more present in Christians than in general. He was more present in the Holy of Holies in Solomon's temple than he was elsewhere. But part of the point of biblical teaching is that God was not contained by the temple.
If you're thinking this is starting to sound a little weird, some recent observations of quantum mechanics have determined or observed that a molecule can exist in more than one place at a time, and that some molecules can pass through other molecules as if they aren't there. These scientific announcements have a "Twilight Zone" aspect to them, but they're current science. We believe that God is everywhere at the same time. Mostly by that we mean nothing escapes his knowledge, nothing is outside of the capability of his power, and there is nothing that can evade his eye, so to speak—hide from him.