How do we know faith in Jesus is necessary for salvation?

The necessity of faith in Jesus for salvation is affirmed throughout the New Testament. In Acts 16:31, Paul states, 'Believe on the Lord Jesus Christ, and thou shalt be saved,' indicating that belief in Jesus is not only central but essential for salvation. Furthermore, Romans 10:9 expresses that if one confesses with their mouth that Jesus is Lord and believes in their heart that God raised Him from the dead, they will be saved. This continuous theme highlights that salvation comes through faith, which is a gift from God, as expressed in Ephesians 2:8-9.