How do we know that Jesus' sacrifice was sufficient for salvation?

In John 19:30, Jesus declares, 'It is finished,' indicating that His sacrificial work was complete. This declaration signifies that the requirements of the law and the demands of justice have been fully met through His blood atonement. Unlike the sacrifices of old, which were temporary, Jesus' one-time offering was sufficient to save lost sinners completely, thus securing a victory over sin, death, and hell. This assured completion of His redemptive work allows believers to trust confidently in Him for their eternal salvation.