In the non-dual state, God, soul and universe are essentially one absolute system which is all-pervading, uncreated, self-luminous and eternal.
In your usual state of consciousness, there is a separate quale experience of everything you observe. But when you transcend into the domain of absolute divinity, all your qualia get mixed up.
There is no such thing as 'God given scripture', 'the messenger of God' or 'the Last Prophet'.
There is no God besides the Self. One who knows the Self, knows God.