How did God exist?

God existed first above all the human race. We all came from the image and likeness of God . The Bible explains everything from the time of Abraham to the coming of Jesus..

I know this much that God caused self, to create self, with self. God is the pure spirit, so pure that it is invisible. It permeates all good things, and does not get dirty even if touches the things impure. He reveals himself only in things good and beautiful; if they are not then He tries to change them to make them good.

If you are looking for what you call as GOD in some corporeal form, you are already off the track. But if you want to call the energy that permeates the universe as GOD, you are close to what you want to know. You are a living example of whatever you think about GOD. Purify your mind -- means get rid of garbage like hatred, anger, passion, ill-will, attachments and all other defilements -- and you will automatically understand everything. GOD is actually just a word or a label pointing to the ultimate truth. If you want to work hard and clean your mind, you can about it at dhamma.org. Here you can join a 10 day residential course and learn the art of "seeing reality as it it". You don't have to believe or not believe in god or whatever, but you have to believe in yourself and your abilities.