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 their 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 records. The record of our bad deeds (including our defective good deeds), along with the just penalties that each deserves, bust 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.
-John Piper, Fifty Reasons Why Jesus Came To Die