The Bible says that Satan is the accuser. Satan holds sin over our heads to make us feel unworthy and trapped in our sin. If we refuse to repent of our sin, we give Satan an opportunity to condemn us. Now you understand why you feel so bad when you harbour unconfessed sin. By doing it, you are giving Satan power over you.
Notice what Jesus said: ‘I will not say much more to you, for the prince of this world (Satan) is coming. He has no hold over Me.’ (John 14:30 NIV) Satan couldn’t point to a single sin in the life of Christ; therefore, he had no power over Him. The good news is that when you are in Christ, Satan loses his power to condemn you too. ‘Therefore, there is now no condemnation for those who are in Christ Jesus.’ (Romans 8:1 NIV)
Will you still sin from time to time? Yes, but when you repent, God will cleanse you, work with you, and give you victory. As long as you are positioned securely in Christ—the One in whom there is no sin—Satan’s condemnation falls on deaf ears, and you live with the joy of knowing God fully accepts you. So, when Satan tries to make you think that you’re not a Christian because you’ve sinned, don’t believe him. Be confident knowing that you can take a powerful weapon out of Satan’s hands simply by confessing your sins and repenting.