“Nevertheless, many even of the authorities believed in Him, but for fear of the Pharisees they did not confess it, so that they would not be put out of the synagogue. for they loved the glory that comes from man more than the glory that comes from God.” John 12:42-43
It is not enough to believe. Many people believe that there is a god of some kind, and many think that all roads lead to Rome-or god in this case. This is in error. It is not enough to believe, nor is it even enough to believe in the right God. There must be a confession. There must be faith.
The men in the passage above belived that Jesus was who He said He was, but they would not confess it. The passages indicates that they had some degree of power or fame or both, but they also had fear. This is what putting ones value in such fickle and temporal things as the glory that comes from men leads to: fear. You may have the glory of men now, but who is to say you will have it tomorrow? You are afraid to be put out of the inner circle of elites. Worse, your are afraid to be put out if the inner circle by the elites, who then will publicly strip you of all you had and held of value.
The blind man in John 9 was not afraid to be put out of the synagogue (though his parents were). He did not know much, in fact, he did not even know who had healed him at first. All he had was a name, for Jesus had sent him to the pool to wash and when he came back, Jesus was nowhere to be found. This did not matter to the blind man. He knew he had been healed and no matter what the pharisees tried to tell him or get him to say, he simply confessed the truth. For this, the pharisees threw him out. But then Jesus shows up and this mans belief and confession are vindicated.
Romans is very clear that one must believe and confess because confession is the mark of faith. It is Christ that saves, through faith. You can believe a fact but to confess that fact as an identity is something else entirely. “Faith is the natural response to seeing God’s faithfulness” (Douglas Wilson). It is not our faith that upholds us, but God’s faithfulness. We simply respond with confession, which does require belief, but not only belief.
Confession is the fruit of faith, not just belief. This is required for Salvation.