Yes, we Lutherans believe that we can be sinners (duh, of course) and at the same time saints, as part of Christ’s body the church. This is one of the great mysteries of the faith, and part of our justification through the death of Jesus on the cross. We have been freed from the penalty of our sin. Isn’t this reason enough to repent every day? Shouldn’t we try to live up to the gift we’ve already been given?