How do we know Jesus' sacrifice secures salvation?

The assurance that Christ’s sacrifice guarantees salvation resides in the efficacy of His atonement, which is explicitly articulated in the gospel. Jesus’ death is not merely a historical occurrence; it functions as the basis for the total redemption of those He came to save. Augustus Toplady's hymn highlights that Christ has made complete atonement for His people, paying every debt incurred by sin. Additionally, Romans 10:4 states that Christ is the end of the law for righteousness to everyone who believes, effectively affirming that through faith in Him, believers receive righteousness. Therefore, His sacrifice is deeply intertwined with both justice and mercy, enabling God to be both just and justifier of the one who has faith in Jesus (Romans 3:26).