1. God is dead (does not exist).
2. Everything is permissible (no Good in itself).
3. We are free (we choose).
4. Future is open (to be forged).
5. Therefore we are forlorn (it is upon us).
6. Thus, we have no excuses.
(a very basic outline of satre's existentialism is a humanism)
Nothing will change if God exists. We can be free and responsible only if God does not exist.