The punishment for speaking Lashon Ha-Ra

Q: How is it possible to explain why one who speaks Lashon Ha-Ra against another has his mitzvot transferred to the person about who he spoke and receives his demerits?
A: This concept is written in the work "Chovot Ha-Levavot" (Obligations of the Heart). We do not have a source for this idea in the Gemara, but the author of "Chovot Ha-Levavot" was one of the early authorities and it seems that he received it as a tradition. It is truly a novel idea but it appears that one who speaks Lashon Ha-Ra against another causes him such great damage, pain and anguish, and the Master of the Universe punishes him in this way.