© 2006 by Robert Lepor. All rights reserved.
The rabbis also expound [from] the [following] pasuk [from Koheles (5; 5) regarding Lashon HaRa bringing physical harm to the speaker]: “Do not allow your mouth to bring sin upon your flesh…” [This verse teaches us]: “Do not speak Lashon HaRa with your mouth, [thus] punishing all of your flesh through this sin.”
Our Rabbis explain the above pasuk in reference to Miriam:
““Do not allow your [your mouth to bring sin upon your flesh]…” – This refers to Miriam, as it is written: “And behold, Miriam was afflicted with tzara’as resembling snow”. (Bamidbar: 12; 10)
“And do not say before the emissary” – This [emissary] refers to Moshe, as it says: “And He sent an emissary and took us out of Egypt”. (Bamidbar: 20; 16)
“For it was negligence” – as it says: “for that which we were foolish and for that which we sinned”. (Bamidbar: 12; 11)
“Why should HaShem be angry concerning your voice?” – Regarding the Lashon HaRa which you (Miriam) spoke about Moshe, as it says: “And HaShem’s Anger flared up against them, and He left”. (Bamidbar: 12; 9)
“And destroy the work of your hands.” Rabbi Yochanan said: With her mouth she sinned and all of her limbs were afflicted, as it says: “And the cloud moved from atop the Tent, and behold, Miriam [was afflicted with tzara'as resembling snow]…” (Bamidbar: 12; 10)”
This [incident involving Miriam] is in line with the following pesukim: “Do not allow your mouth to bring sin upon your flesh…” (Koheles: 5; 5) and “One who guards his mouth and tongue [guards from troubles of his soul].” (Mishlei: 21; 23)
 This teaching is found in Parshas Ki Teitze, Piskah 275.
 This teaching is found in Parshas Devarim, Piskah 1.
 The phrase “Kal Va’chomer”, literally meaning “light and stringent” is used to introduce, or can refer to, an a fortiori argument, whereby one draws a conclusion that is inferred to be even more certain than another accepted conclusion. There are ten places in TaNaCh (written Torah, including the Torah, Prophets, and Scriptures) where there are Kal Va’chomer’s, one of which (Bamidbar: 12; 14) where HaShem tells Moshe that Miriam must be quarantined for seven days for her sin of slandering Moshe. HaShem tells Moshe, “…and if her father would spit in her face, would she not be ashamed for seven days…”, how much more should Miriam be ashamed for seven days for her sin of Lashon HaRa.
 The pasuk from Koheles (5; 5) reads: “Do not allow your mouth to bring sin upon your flesh, and do not say before the emissary ‘for it was negligence’. Why should HaShem be angry about your voice and destroy the work of your hands?”
 RaSh”I, quoting a Midrash, explains that “the work of your hands” refers to a person’s good deeds which can be lost as a result of the sin of speaking Lashon HaRa.
 This teaching can be found in Vayikra Rabba: 16; 5, Koheles Rabba: 5; 5, and Shocher Tov, Tehillim 52.
 The Hebrew for emissary is “Malach”, meaning either “angel” or “emissary”. The term “Malach” is to be understood as “emissary” in the pasuk quoted from “Koheles”, while the quoted phrase from the Torah refers to “angel”. RaSh"I, on the pasuk in Bamidbar, explains that the usage of “Malach” comes to teach that one should regard Torah leaders as akin to angels.
According to the Sforno, “for it was negligence” refers to one who is explaining that he did not fulfill his obligation due to negligence. Aharon said to Moshe: “that we were foolish and that we sinned” when explaining why he and Miriam took part in Lashon HaRa against Moshe. Therefore, both verses relate to one another as they provide some sort of attempted explanation for their misdeed.