How do we know that Christ's death is vital for salvation?

The death of Christ is central to the doctrine of salvation in Reformed theology, as it directly addresses the consequence of sin, which is death (Romans 6:23). Jesus, as the Lamb of God, bore our sins, dying in our place as our substitute, fulfilling the law's requirements (Isaiah 53:5). In Matthew 16:21, the necessity of His death is stated explicitly; without His death, there would be no atonement for sin, and thus no salvation for the elect. This principle is echoed throughout scripture, such as in Galatians 4:4-5, which speaks of Christ's redemptive work under the law. Only through His sacrificial death can we be justified before God, highlighting the profound significance of the cross in the Christian faith.