How do we know salvation is through Christ alone?

The New Testament consistently affirms that salvation is found in Christ alone. For instance, in Matthew 1:21, the angel declares that Jesus will save His people from their sins, underscoring His role as the sole Savior. Similarly, Ephesians 2:8-9 emphasizes that we are saved by grace through faith, and this not of ourselves; it is the gift of God, not of works, lest anyone should boast. This highlights that our salvation does not depend on our efforts or merits but solely on Christ's finished work on the cross, where He bore the punishment for our sins and provided a complete atonement.