Why would God condemn all and only those that don't believe in God? I am not saying God, if there is such a thing, could not condemn or forgive anyone. But is there anything but scriptural support for the claim that faith in God is the essence of eternal salvation or similar? It might be that the damned make a free choice to "separate" themselves from God, but do we truly choose our ontological beliefs?
There are various arguments that are advanced to motivate religious belief. One of the most interesting and popular is a wager argument often associated with Pascal (1623–1662). It is designed to offer practical reasons to cultivate a belief in God. Imagine that you are unsure whether there is or is not a God. You have it within your power to live on either assumption and perhaps, through various practices, to get yourself to believe one or the other. There would be good consequences of believing in God even if your belief were false, and if the belief were true you would receive even greater good. There would also be good consequences of believing that there is no God, but in this case the consequences would not alter if you were correct. If, however, you believe that there is no God and you are wrong, then you would risk losing the many goods which follow from the belief that God exists and from actual Divine existence. On this basis, it may seem reasonable to believe there is a God.
In different forms the argument may be given a rough edge (for example, imagine that if you do not believe in God and there is a God, hell is waiting).
Where does the bit in bold actually come from if not just the bible? As far as I can tell, pretty much everyone believes in some form of Sola Fide, Catholics too, it just takes different forms, e.g. "good works" as an essential function of proper faith.