Why does Christ's death and resurrection matter for salvation?

The death of Christ pays the penalty for sin, thereby satisfying the justice of God (Romans 5:8). His resurrection is equally essential because it confirms that He has triumphed over sin and death, which deems Him the sole Savior of humanity. If Christ had not risen from the dead, then His sacrifice would not hold power to save; instead, it is His victory that assures believers of their own resurrection and eternal security (1 Peter 1:3-4). Additionally, these events underscore the sovereignty of God's plan for redemption, highlighting that it is through Christ alone that grace is offered to all who believe (Ephesians 2:8-9).