How do we know that Christ's crucifixion is central to salvation?

The centrality of Christ's crucifixion to salvation is emphasized in both the Old and New Testaments. In John 3:14-15, Jesus refers to the lifting up of the bronze serpent as a typology of His own crucifixion. Just as Israelites were healed by looking at the serpent, humanity is spiritually healed by looking to Christ crucified. The message of Jesus’ death and resurrection is foundational for the faith, as encapsulated in Romans 10:13-15, demonstrating that faith in Christ's work on the cross is what grants us salvation.