One of the weapons which Satan frequently uses to fire his darts into the heart of sincere and devoted Christians is none other than condemnation. Condemnation is one of his best weapons since it makes the heart, the inner part of our beings, ill. It is a powerful weapon of Satan to corrupt our fellowship with God. I John describes the effects of this disease which affects many Christians. Note also that the reference is to the heart.
Condemnation is a serious disease that affects the heart, the inner being of a man.
When there is condemnation in our hearts then there is no confidence before God and if there is no confidence before God, then I really question of the fellowship that we are able to have with God. It is however impossible to rejoice in Him when you do not have confidence before Him. You see, we are accustomed to reading this verse using a preconceived idea of righteousness by works. Thus, we think that the righteousness referred to in that verse is our self-righteousness. It is not an armour that we constructed.