Our Gemara on Amud Beis describes a process to help cure a tree that is losing its fruit; one to draw attention so people will pray, and another that helps the tree avoid overproducing blossoms and getting too weighed down to sustain its growth: “If there is a tree that sheds its fruit prematurely, one may paint it with red paint and load it with stones.”

Ben Yehoyada says this hints at the process of the sin of l’shon hara. One who speaks l’shon hara loses his mitzvos and they are given over to the victim of his gossip. This is the tree that loses its fruits. What is the remedy? He wraps himself with the red paint (which is like makeup, as used in Yeshaiyahu (3:16), a form of beautification, reminiscent of) Torah, and then weighs his branches with stones, which is reminiscent of prayer. (Ben Yehoyada says stones are symbolic of prayer, as the Zohar reads the verse (Devarim 27:6) instructing the Jewish people to build an altar out of “complete stones,” as a directive to “build” prayers out of complete, wholesome and pure thoughts.)

Leaving aside how evident this derash is, the actual tradition that one who speaks l’shon hara ends up giving his mitzvos to the victim bears study. Where is the source? It is not in the Gemara or Midrash. How could this possibly be remotely fair?

Perhaps the earliest mention of this idea comes from Chovos Halevavos (The Gate of Submission, 7):

“It is told of a pious man about whom someone spoke badly of, that when he heard of this, he sent a basket full of the choicest fruits of his province to the one who spoke badly of him and wrote to him: ‘I have been notified that you sent me an offering from your merits, and I am sending you this gift in return.’

Similarly, some people will find in their book of sins, sins they did not do, and when they will protest saying ‘we did not commit these things,’ they will be told ‘these were added to the list of your misdeeds for having spoken of this or that person.’”

Orchos Tzadikkim (The Gate of Humility) states, “On the Day of Judgment they will display before many people good deeds that they did not perform, and these people will say, ‘But we did not perform these precepts.’ Then the Court of Heaven will answer them, ‘Those people who spoke evil of you performed these good deeds and we are taking them away from them and giving them to you.’”

Rav Yosef Karo (Maggid Meisharim, Vayakhel) states that one should not be aggrieved if somebody speaks ill of him, rather, he should be thrilled, because they are deducting from his merits and giving it to him.

The Chofetz Chaim (Shmiras Halashon, Gate of Remembrance, 7) states the source is really a Midrash:

“Come and see further how great is the punishment of this bitter sin. For by speaking lashon hara and rechiluth he loses the little Torah that he has. As per Midrash Shocher Tov 42 (Koheleth 5:5): ‘Do not allow your mouth to cause sin to your flesh.’ This speaks of lashon hara, etc. ‘Why should G-d be angry at your voice?’ — at that voice which you uttered with your mouth and spoke lashon hara against your friend. ‘And [He shall] destroy the work of your hands’ — the little Torah that you have in your hands will go lost.” And it is obvious that the intent of the midrash is as written in the holy books, that one who speaks l’shon hara against his friend causes his merits that have accrued until now to be taken from him and given to his friend.

It is indeed difficult to see how this is fair. Imagine how a repugnant and evil person who has spent his entire life sinning could at one moment lose all of his sins and get the merits from a righteous person, who in a weak moment, spoke slanderously of him?

A possible approach offered by some is that if you pay attention to the language of some of the prior sources, you will notice that it does not state “all” of his merits, but rather “from” his merits or “a portion” of his merits. (See Rav Shlomo Rosner, Kuntres Shmiras Halashon 5), although this does not seem to be the approach of the Chafetz Chaim. However, if we do take this approach, then I would take it further so that we could understand this idea as follows: If one speaks l’shon hara about a person, slandering him that he committed a particular sin or misdeed, in retribution, that particular sin will now be transferred from the victim of the gossip to the perpetrator. Because that is middah k’neged middah, poetic justice.