"If you are a preacher of Grace, then preach a true, not a fictitious grace; if grace is true, you must bear a true and not a fictitious sin. God does not save people who are only fictitious sinners. Be a sinner and sin boldly, but believe and rejoice in Christ even more boldly. For he is victorious over sin, death, and the world. As long as we are here we have to sin. This life in not the dwelling place of righteousness but, as Peter says, we look for a new heavens and a new earth in which righteousness dwells. . . . Pray boldly-you too are a mighty sinner."
(Weimar ed. vol. 2, p. 371; Letters I, "Luther's Works," American Ed., Vol 48. p. 281- 282)