How do we know that Christ's death was necessary?

The necessity of Christ's death is rooted in God's perfect justice and holiness. God's nature demands that sin be adequately dealt with, which is why He cannot simply overlook it. In Luke 24:46, it states that it was necessary for Christ to suffer and rise again, affirming that His death was essential to meeting the demands of God's justice while providing salvation for His elect. Christ's sacrifice satisfies divine justice, proving that God's love and justice are perfectly harmonized in the redemptive work of Jesus.