The ordinary concept of God among Christians is a concept of a person because God is called a person in the Athanasian doctrine of the Trinity. The better educated, though, claim that God is invisible. This is because they cannot understand how a human God could have created heaven and earth and filled the universe with his presence, along with other things that pass the bounds of understanding as long as people do not realize that Divinity is not in space. Still, people who turn to the Lord alone think of one who is both divine and human, and therefore think of God as a person.
We may gather how important it is to have a right concept of God from the fact that this concept is the very core of the thinking of anyone who has a religion. All the elements of religion and of worship focus on God; and since God is involved in every element of religion and worship, whether general or particular, unless there is a right concept of God there can be no communication with heaven. This is why every nation is allotted its place in the spiritual world according to its concept of a human God. This [understanding of God as human] is where the concept of the Lord is to be found, and nowhere else.
We can see very clearly that our state after death depends on our avowed concept of God if we consider the opposite, namely that the denial of God, and in the Christian world, a denial of the Lord’s divinity, constitutes hell.
from Divine Love and Wisdom, Sections 12, 13