The core message of christianity is all have sinned and fallen short of the glory of God. That means our deeds and works hold no real value in of themselves, other than to lift ourselves up before other men. So in order to be found righteous before God we must seek atonement for sin.
The answer is no to your follow up. For if we had no God then there could be no atonement.
The answer is no to your follow up. For if we had no God then there could be no atonement.