How do we know that Jesus’ sacrifice was complete?

In John 19:30, Jesus declares 'It is finished' at the moment of His death, which signifies the completion of His redemptive work. This statement indicates that every demand of God's law has been fully satisfied in His sacrifice. Jesus accomplished everything necessary for salvation, including the fulfillment of Old Testament prophecies and the satisfaction of God's justice for the sins of His people. This final declaration assures believers that there is nothing more to be added to their salvation; it was entirely performed by Christ alone, showcasing the doctrine of justification by faith alone as rooted in His finished work.