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

The effectiveness of Christ's death is rooted in the doctrine of sovereign grace, where His sacrifice is not merely potential but actual. Hebrews 10:10 states that 'we are sanctified through the offering of the body of Jesus Christ once for all,' emphasizing that this work not only fulfills the law but establishes a new covenant of grace. Furthermore, Acts 2:23 highlights that Christ was delivered by God’s predetermined plan, affirming that His death was intentional and resulted in the redemption of His people. Therefore, it is affirmed that He accomplished a complete atonement, ensuring that all for whom He died are indeed saved.