What Is The Will Of God?

Can we do something outside the Will of God? Since God is One, He is all that exists, and we are part of that Oneness. His Will cannot be separate from Him or the Oneness or you. If you do something that you "think" is outside His Will, is it truly outside His Will, or does it just appear that way, similar to a play on the stage that might appear real if you temporarily get immersed in it? Can you ever describe what His Will is?