From the Wartburg Castle, where Luther was in hiding following the Diet of Worms, Luther wrote to Philipp Melanchthon (Aug 1 1521) a confronting but certainly misunderstood hyperbolic diction:
‘If you are a preacher of grace, then preach real and not fake grace. If grace is true, then you must bear true and not false sin. God does not save those who are only fake sinners. Be a sinner — believing and rejoicing in Christ more boldly than you sin. And do so because Christ has overcome sin, death, and the world. If we are in this world, then we cannot help but sin. Our existence is not the dwelling place of righteousness. As Peter says, we look for new heavens and a new earth in which righteousness dwells. It is enough that by the bounteous glory of God, we have come to know the Lamb who takes away the sin of the world. No sin will separate us from the Lamb, even though we commit adultery and murder a thousand times a day. Do you think that the purchase price that was paid for the redemption of our sins by so great a Lamb is too small? Pray boldly — you are also a huge sinner.’
Luther was not promoting licentiousness here rather he was seeking to promote the all-surpassing sufficiency of the righteousness that the Lamb of God – alone – has earned for us. A righteousness which saves to the uttemost sinners like us. Unless you are a sinner you will not receive Christ’s righteousness. If you are a sinner you can know, by faith alone, that there is no sin – no sin – that can ‘out sin’ Christ’s merit of righteousness for us.
Thus a fake sinner will only merit a fake saviour. A true sinner will, by faith alone, merit the righteousness and forgiveness of a true saviour. Be a sinner!