We know Christ's work was finished because He declared it so and demonstrated His victory over sin, death, and the grave through His resurrection.
Christ's assurance that His work was finished is underscored by His resurrection, affirming that He successfully accomplished the mission given to Him by the Father. In John 17:4, He states, 'I have finished the work which thou gavest me to do,' indicating the certainty of His mission's success even before the crucifixion. The resurrection serves as powerful evidence of this finished work, showing that He conquered sin, death, and Satan. In Romans 10:4, it states that 'Christ is the end of the law for righteousness to everyone that believeth,' reinforcing that His obedience and sacrifice fulfill all that was required for the redemption of His people, making it clear that His work is indeed complete.
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