How do we know Christ's death is significant?

Christ's death holds profound significance as it is the means by which believers are reconciled to God, satisfying the demands of divine justice. As Paul expounds in 2 Corinthians 5:21, Christ became sin for us so that we might be made the righteousness of God in Him. This transaction occurs at the cross, where Christ's perfect sacrifice pays the penalty for sin, enabling Justification for sinners. Without the death of Christ, irrespective of how righteously He lived, humanity would remain estranged from God. Therefore, Christ's death is central to the Gospel, as it is the culmination of God's plan for redemption.