How do we know that Jesus' sacrifice was sufficient?

In John 19:30, Jesus exclaims 'It is finished,' which serves as a powerful declaration of the fulfillment of all that was necessary for our salvation. This phrase means that the debt for sin has been fully paid and that the work of redemption, which included fulfilling the law and satisfying God's justice, was completed. This assurance allows believers to rest in the fact that our standing before God is entirely grounded in Christ's completed work, rather than any human effort. Our salvation is not an ongoing work that we must strive to maintain but is assured in the perfect and finished sacrifice of Jesus Christ, who is the pioneer of our faith.