How much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God.
Heb 9:14 ESV
To disfigure the Cross is to attempt to add our good works to Christ’s perfect, complete work on the Cross.
Good works cannot achieve right standing before God. However, a faith-filled salvation will produce many good works. Good works are the fruit of salvation, not its cause or basis. Good works flow from Christ’s grace enabling us to pour out costly love for and on behalf of others.
Good works cannot earn God’s favor. Good works cannot gain God’s approval. Good works do not obligate God to forgive us. Good works cannot replace a salvation that only a sinless, beautiful Savior accomplished for us in his death and resurrection.
To add to the finished work of Jesus Christ is to disfigure it, mar it, and destroy it altogether. There is nothing you can contribute to the payment that Jesus made on the cross for sin. There is no penance you can undergo, no good work you can perform, no pilgrimage upon which you can embark, no punishment you can endure to clear your guilt before God. When Jesus said, ‘It is finished.’ he meant it.
He meant that he had completely paid the price to release his people from their bondage to sin. So for you to try to pay for your own sins is to deny that Jesus really did finish paying for sin. For you to try to do something to earn your own salvation is to make Jesus Christ out to be a liar.
James Montgomery Boice and Philip Graham Ryken, The Heart of the Cross (Wheaton, IL: Crossway Books, 1999), 52.