How do we know that not all faith is saving faith?

The sermon clarifies that faith without confession is not true saving faith, as seen in John 12:42-43. Many of the Jewish leaders believed in Jesus, but their fear of losing social standing led them to hide their faith instead of publicly confessing it. This reflects the biblical truth that committing oneself fully to Christ is essential for true salvation. The preacher highlights that faith involves both belief and a willing commitment to accept Christ as Lord, emphasizing that knowing about Christ is not the same as truly believing in Him.