My thoughts.. God is consciousness, God is all there is, God is everywhere and everything, God is light.
It is the world and the Universe.
It is me as it is you.

We are little light particles, living cells within God's body;
Yet those cells are so expansive and huge, that they themselves are Universe's!
All pieces of the giant energy Source that creates it all.

An individually unique puzzle piece,
Like that of a snowflake,
That fits in your intricately perfect spot within it all.
Everything is like layers of light, over and over, caked in energy layers that create our very fabric of reality.
And it's all One and it's constantly flowing and evolving.
He is everything and he is nothing.
What God is...
We as humans probably don't even have decent words for.