1 John 1:8–9 (NKJV)
"8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness."
If you are a true Christian you really need to read this and pay close attention to the following words. If and when you sin as a Christian, you must beware of allowing guilt and condemnation to go too far. What do I mean? Once you confess your sins to God, after you have asked Him to forgive you for some failure, you must guard your mind and heart against condemning thoughts that are negative that produce a feeling of alienation against God.
No, I am NOT speaking to those who live in willful rebellion against God, I am speaking to those who love Jesus Christ, but stumble and fall. You must believe that God forgives you when you confess your sins. Beating yourself down, saying negative things about yourself, and feeling unworthy to come to Jesus are all things that seem humble, they seem good, but they are not good.
These negative condemning thoughts produce alienation from the very One who saves you and cleanses you from your sins. We believe the Word of God? Then we have to believe the scriptures that tell us God forgives us and cleanses us from our sins, by the blood of His Son Jesus Christ, if we will confess.