Is one not exceedingly embarrassed to praise HaShem with the same mouth with which he uttered mundane speech? [The above] follows that which is taught in the Yerushalmi, where we learn of] the [following] saying: “Who would provide me with two mouths, one to speak of my household necessities, and one to speak with my Creator? So too, now, [with regards to obscene speech, how will one] with an impure mouth, organize [his prayer] before [HaShem] Yisbarach [in order] to seek a desirous [response from HaShem], for how will his words [of prayer] be desired [by HaShem]? Can it be that the advocate is [also] the prosecutor? For when one speaks with this [impure mouth, in order to beseech HaShem’s merciful response, that same mouth] will [also serve as a] reminder of [the] sins [that he committed with that mouth]. See over there, [in the Alschich], where he brings a teaching of our Sages of Blessed Memory in reference to the aforementioned.
[The Alschich] concludes this [teaching] with the following: “The [following] is what our Torah is coming to teach when it says “and it shall be on Aharon…”: Just as the m’eel of the Kohen Gadol, of which we spoke earlier, shall be upon Aharon to serve HaShem [while he wears] it, and he shall not [be lacking] that vestment, [so too must one ensure that his speech, which is compared to the m’eel, is pure, so that his mouth remains an appropriate vessel to use in his prayers before HaShem. Only] when the Kohen Gadol is wearing all of the necessary vestments, his] “voice shall be heard” in his prayer, when he comes into the Holies to speak with [HaShem] Yisbarach. [However], this is not the case [if he lacks the required vestments], Heaven Forbid.” [Similarly, when one desires his prayers to be accepted, he should keep his speech pure and, thereby, HaShem will listen to his prayers.]]
 This teaching is found in his book “Toras Moshe”, Parshas “Titzaveh”, (28; 31), at the conclusion of that section, beginning with the words “v’al ha’shevi’is”).
 The whole verse states, “And it shall be upon Aharon to serve [before HaShem], and its sound shall be heard when he enters the Holies before HaShem and when he leaves, and he shall not die.” From here we see that if the Kohen Gadol (High Priest) is not wearing one of his garments when he enters the Holies, he is liable for the death penalty at the hand of Heaven. This verse is preceded by verses that describe different vestments that the Kohen Gadol shall wear. The verse immediately preceding the aforementioned verse, states that Aharon shall wear the m’eel – the cloak of the Kohen Gadol that is adorned at the bottom with small imitation pomegranates and bells.
 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.
 This teaching is found in the Talmud Yerushalmi, maseches “Berachos” (chapter 1, halacha 2).