How do we know that Jesus finished His work on the cross?

The assurance that Jesus finished His work is foundational to the Christian faith. In John 17:4, Jesus says, 'I have finished the work which thou gavest me to do.' This statement, along with His final declaration on the cross, 'It is finished' (John 19:30), resonates throughout scripture, affirming the successful completion of His redemptive mission. The theological implications are profound; His work encompassed the fulfillment of the law, the payment for sin, and the provision of salvation for all those given to Him by the Father.

By living a sinless life and fully obeying God's commands, Jesus perfectly upheld the law's divine standard, satisfying God's justice. A central tenet of sovereign grace theology is the belief in Christ's substitutionary atonement—He bore the sin of those who would believe, accomplishing a full and complete salvation. His resurrection further validates this work, demonstrating that death has no claim over Him—and thus, no claim over those He saves. The certainty of our salvation rests upon this finished work, allowing us to trust fully in His promise of eternal life.