God knows everything, but this does not eliminate man’s responsibility to confess his sins. Failure to do so forfeits God’s practical forgiveness.
Most people view sin as a private or earthy matter. Yet, every sin is against the Lord. In truth, men can sin against the Father, the Son, and the Spirit.
Paul’s salutation was so important to him that although he did not personally pen most of his epistles, he personally penned his salutation.