I heard Dr. Jono Linebaugh share a version of the following in a sermon he preached at Coral Ridge Presbyterian Church.
Martin Luther’s Encounter with Satan
In the conversations of Luther, which are in some measure a post-humous publication, we read, that . . . Satan, either in reality or in a dream, appeared in the depth of the night, and addressed him in the following terms: “Luther, how dare you to pretend to be a reformer of the Church? Luther, let your memory do its duty – let your conscience do its duty: you have committed this sin – you have been guilty of that sin; you have omitted this duty, and you have neglected that duty: let your reform begin in your own bosom. How dare you attempt to be a reformer of the Church?”
Luther, with the self-possession and magnanimity by which he was characterized, (whether it was a dream or reality, he himself professes not to decide,) said to Satan – “Take up the slate that lies on the table, and write down all the sins with which you have now charged me; and if there be any additional, append them, too.” Satan, rejoiced to have the opportunity of accusing, just as our blessed Lord is rejoiced to have the opportunity of advocating, took up a pencil, and wrote a long and painful roll of the real or imputed sins of Luther.
Luther said, “Have you written the whole?” Satan answered, “Yes, and a black and dark catalogue it is, and sufficient to deter you from making any attempt to reform others, till you have first purified and reformed yourself.” Luther said, “Take up the slate and write as I shall dictate to you. My sins are many; my transgressions in the sight of an infinitely holy God, are countless as the hairs of my head: in me there dwelleth no good thing; but, Satan, after the last sin you have recorded, write the announcement which I shall repeat from 1 John 1:7,“The blood of Jesus Christ cleanseth from all sin.” Luther in that text had peace; and Satan, knowing the source of his peace, had no more advantage against him.
by Rev. John Cumming, 1854
(credit to www.loveallpeople.org/pearl-luther.html)