How do we know Jesus' sacrifice was effective for our sins?

The effectiveness of Christ's sacrifice is rooted in the nature of God’s holiness and justice. God cannot simply overlook sin without upholding His law; thus, the sacrifice of Jesus, who knew no sin, was essential to satisfy divine justice. In Isaiah 53, we see that the Lord laid on Him the iniquity of us all, making Him sin for us. When Christ died, He did not just die an ordinary death; His death was the fulfillment of God’s plan for redemption, which allowed Him to be both just and the justifier of those who believe in Him. The shedding of His blood was necessary for the remission of sins, emphasizing that His sacrifice was comprehensive and assured for those whom He came to save.