How do we know Christ's death was sufficient for salvation?

The sufficiency of Christ's death for salvation is underscored in numerous passages throughout scripture. For instance, Isaiah 53:5 states, 'By His stripes we are healed,' affirming the efficacy of His suffering for our transgressions. Furthermore, in Romans 5:8, we learn that 'God commendeth His love toward us, in that, while we were yet sinners, Christ died for us.' This indicates that His sacrifice was intentional and effective for the elect, those redeemed before the foundation of the world. The assurance of salvation rests on the completed work of Christ, which validates God's mercy and justice as He can justly forgive sins through Christ's atonement.