God may forgive me, but I can't forgive myself. This statement may be another form of pride masking as false humility. God, the Judge and Arbiter in the highest courtroom, pronounces you 'not guilty' by virtue of what Christ has done for you on the cross. But when you make this statement, you function as the judge and arbiter in a much lower court and overrule the higher court's decision. This reveals contempt for God's stature as the ultimate Judge. If you do not see your daily need of the mercy of Christ and do not experience it regularly, you will not extend it to others when they sin against you.