Why is it important for Christians to understand the fullness of Jesus' sacrifice?

For Christians, grasping the fullness of Christ's sacrifice is essential for their faith and assurance. It highlights that salvation is solely by grace through faith in what Christ accomplished on the cross (Ephesians 2:8-9). Recognizing that His sacrifice was perfect and complete eliminates the burden of trying to earn God's favor through our own works. It fosters a deep assurance that believers can rest in the security of their salvation, knowing that they are clothed in His righteousness and forever reconciled to God (2 Corinthians 5:21). The significance of His last words comforts and strengthens the believer's relationship with Christ, teaching them to rely solely on His merit.