‘God’ is present in all places; however, our conception of Him must not be of Him filling space, as water fills a jug,
for He has no physical or material dimensions.
So, by omnipresence we mean that God, in the totality of his essence, without diffusion or expansion, multiplication or division, penetrates and fills the universe and beyond in all its parts.
God’s essential presence is without any division of Himself
God’s omnipresence is not the presence of a part but of the whole of God in every place. This follows from the conception of God as incorporeal (God is a pure and most simple spirit, without material parts).
Hence it is wriiten : “God is Spirit”.
God’s presence is not a multiplication of Himself
There is no multiplication or diffusion of God’s substance to correspond with the parts of his dominions. The one essence of God is present at the same moment in all.
His essential presence everywhere is not by multiplication, for the simple reason that the infinite God cannot multiply Himself, or make Himself more or greater than what He is.
‘God’ is then totally everywhere.