The cross reminds us that our good deeds are unable to save us. In his book, Fifty Reasons Why Jesus Came to Die, John Piper explains:
What a folly it is to think that our good deeds may one day outweigh our bad deeds. It is folly for two reasons.
First, it is not true. Even our good deeds are defective because they don’t honor God in the way we do them. Do we do our good deeds in joyful dependence on God with a view to making known his supreme worth? Do we fulfill the overarching command to serve people “by the strength that God supplies–in order that in everything God may be glorified through Jesus Christ” (1 Peter 4:11)?
What then shall we say in response to God’s word, “Whatever does not proceed from faith is sin” (Romans 14:23)? I think we shall say nothing. Whatever the law says it speaks…so that every mouth may be stopped” (Romans 3:19). We will say nothing. It is folly to think that our good deeds will outweigh our bad deeds before God. Without Christ-exalting faith, our deeds will signify nothing by rebellion.
The second reason it is folly to hope in good deeds is that this is not the way God saves. If we are saved from the consequences of our bad deeds, it will not be because they weighed less than our good deeds. It will be because the “record of [our] debt” in heaven has been nailed to the cross of Christ. God has a totally different way of saving sinners than by weighing our deeds. There is no hope in our deeds. There is only hope in the suffering and death of Christ.
There is no salvation by balancing the records. There is only salvation by canceling the records. The record of our bad deeds (including our defective good deeds), along with the just penalties that each deserves, must be blotted out–not balanced. This is what Christ suffered and died to accomplish.
The cancellation happened when the record of our deeds was “nailed to the cross” (Colossians 2:13). How was this damning record nailed to the cross? Parchment was not nailed to the cross. Christ was. So Christ became my damning record of bad (and good) deeds. He endured my damnation. He put my salvation on a totally different footing. He is my only hope. And faith in him is my only way to God.
Our good deeds will not do. Instead, we must cling to the cross of Christ for salvation.
Scripture Meditation: And you, who were dead in your trespasses…God made alive together with him, having forgiven us all our trespasses, by canceling the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross. (Colossians 2:13)
Source: Piper, John. Fifty Reasons Why Jesus Came to Die (Wheaton, Crossway, 2006) 32-33.