You must be careful.. If there is a thing called "eternity" how can an eternal PAST be NOT possible.. Did God appear by magic?.. It is possible that this universe had a beginning but then there must be "something else" besides this universe THEN.. for God to reside in.. Some kind of UGH... DIMENSION..
The SPIRITUAL dimension!!(pipe organ plays ominous chord with flourishes)..
Did you want to stuff God into some dimension that would facilitate this communication between Him and Man? (Questions of dimensionality seem related to considerations of relative Time -- but God is not in Time at all.)
Do you think God needs a dimension in order to operate? If so, what of His Omnipotence? (It seems to me a God who "needs" cannot be omnipotent.)
You know that I am attracted to Sir Isaac Newton's idea of the sensorium Dei, which as I understand it, is some sort of universal field-like interface between the spiritual kingdom and the created world. But God is not "in" the interface; He is beyond it.
Yet I have reason to believe that Newton thought of the sensorium Dei as the God-designed, universal facilitating means by which the Lord of Life can be with His creatures, without "over-determining" the Creation.... perhaps it represents the "waters above?" [And here's an additional speculation: a universal zero-point vacuum field may represent the "waters below"; both facilitate "inputs" from a divine "beyond," the "waters above" referring to influx of Spirit, the "waters below" to the influx of virtual matter -- e.g., photons (light) -- essential to the maintenance of physical creation. On this model, both "above" and "below" are divine in origin and constant impulse. But I digress....]
Think of it: If God the Creator were physically "in the world," His mere Presence would utterly determine all possible outcomes; there would be no freedom of development of the Creation according to His Laws; and human free will would be a fantasy.
Anyhoot, whether or not this understanding is correct -- and I have long meditated and prayed over these issues -- my sense is there isn't a dimension "big enough" to "hold" God.
So call me crazy. FWIW my dearest brother in Christ....