God exists as the past exists in relation to the present. He is the immutable, perpetual ground of being on and out of which the present "floats" as a phenomenal and substantial reality.
God, also, exists as the future exists in relation to the present. He is the field of infinite being into which the present thrives as a perpetually unfolding reality.
Neither the past nor the future "exist" in a positivist sense, nor in a materialist sense. But they truly exist. Likewise, while God does not exist in a positivist or materialist sense, He does truly exist.
The eternity of God is to time (by which I mean spacetime) what the past is to the present state of affairs as each present time, t. The infinity of God is to time (ditto) what the future is to the present state of affairs as each present time, t.
God is the immaterial but transcendentally necessary source and goal of the present, and the present world. Arguments denying His existence are formally equivalent to arguments that deny the substantial reality of the past and or future.