Thomas Brooks, an old English puritan, said it well, “That sorrow for sin that keeps the soul from looking towards the Mercy Seat, and that keeps Christ and the soul asunder, or that shall render the soul unfit for the communion of saints, is a sinful sorrow.” This is what illegitimate guilt, shame, and regret will do. But godly sorrow cuts the heart and press the soul unto repentance. This is the sorrow described by the apostle in 2 Corinthians 7:9–10
9 Now I rejoice, not that you were made sorry, but that your sorrow led to repentance. For you were made sorry in a godly manner, that you might suffer loss from us in nothing. 10 For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death.
We sing: “What can wash away my sins? Nothing but the blood of Jesus.” Yet our minds are beaten down and held captive by guilt, shame, and regret deceiving us into believing that the blood of Jesus did not “wash away my sins” thoroughly enough to keep them forgiven. We hear the lies and begin to be persuaded that somehow our past sins can come back, overcome the power of the blood of Christ, and make us guilty again. I do not deny that these thoughts can be loud and powerful, but they are lies. For it is written, “Therefore, if anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new (2 Corinthians 5:17).” Concerning that previous “you” who was alienated from God, it is written: “For you died, and your life is hidden with Christ in God (Colossians 3:3).” And concerning the accusations of your past, those sins which were cast away from you and from God as far as the east is from the west (Psalm 103:12), it is written: “Who dares accuse us whom God has chosen for his own? No one—for God himself has given us right standing with himself. Who then will condemn us? No one—for Christ Jesus died for us and was raised to life for us, and he is sitting in the place of honor at God’s right hand, pleading for us [Romans 8:33–34 (NLT)].