Furthermore, you should know, that one who wishes to be completely careful [in avoidance] of the sin of accepting Lashon HaRa and Rechilus, should constantly accustom himself to rebuke the members of his household [to refrain from involvement in this sin] and [should] explain to them the greatness of the reward for one who is careful with his speech. On the flip side, [he should describe] the great punishment [meted out for forbidden types of speech such as Lashon HaRa and Rechilus], May the Merciful One spare us [from such punishment. The individual should explain the above to members of his family] in order that he will not fall into the net of acceptance of Lashon HaRa and Rechilus as a result of their tales [within which is included forbidden speech]. [For] further [discussion on this matter], see [sefer] “Chofetz Chaim”.
 “Amen” means “true”, is a statement that we agree with the blessing that was recited, and an assertion that we believe that HaShem will fulfill His word. “Amen yihei Shmei Rabbah…” is a response in the Kaddish prayer, where the congregants answer “Amen. His great Name shall be the source of blessing forever.” Tosafos on maseches Berachos, 3a, discuss the meaning of “Yihei Shmei Rabbah…” Tosafos quotes Machzor Vitri as stating that “Yihei Shmei Rabbah…” is a prayer that HaShem’s Name will be complete, which will occur after the destruction of the nation of Amalek, which will occur at the time of the Redemption. The second prayer is that HaShem’s Name will be a source of blessing for The World to Come.
The existence of Amalek diminishes HaShem’s Name, as it says, “for a hand is on the throne of HaShem, [it is] a war for HaShem against Amalek from generation to generation.” (Shmos: 17; 16) RaSh”I, quoting from Tanchuma (end of Parshas Ki Seitzei), tells us that in the pasuk, the Name of HaShem is written incomplete, with only the first two letters of His Name, as Amalek continues to exist. Amalek is the nation that was first to attack the invincible Jewish nation after the Exodus from Egypt (Shmos: 17; 8) due to their hatred of HaShem and His People, as the Jews are HaShem’s representatives in this world. Tosafos quotes the end of maseches “Sotah” as teaching that answering “Amen Yihei Shmei Rabbah…” to the Kaddish D’Rabanan (Kaddish which follows Torah learning) is so powerful that it is one of the things that is responsible for the continued existence of the world.
The gemara in maseches Shabbos, 119b states that if one says “Yihei Shmei Rabbah…” with all of their power, the negative decree directed against him is torn up. RaSh”I explains that answering with all one’s power refers to “all of one’s concentration (kavana)”.
 “Beis Midrash” means “House of Study” and is the place where Torah is commonly studied and taught.
 [Chofetz Chaim’s note: Regarding this [matter of those who are regularly involved in forbidden speech, even [when they are] in the synagogue and Beis Midrash, I have explained by way of a hint that which our wise men, of Blessed Memory, have said in [maseches] “Berachos”, 6a: “These garments of the rabbis became worn out due to their rubbing.” For, “garments” hint to the performance of mitzvos, which are given the name “clothes for the soul”, as the GR”A has written in Mishlei. The habitual speakers of Lashon HaRa bring about real damage to the body and to the soul, as is [discussed] in a number of places.]
RaSh”I explains on the gemara from Berachos that the worn clothing is due to the mazikin that rub against the clothes of the Torah scholars. “Mazikin” literally means “damagers” and refers to certain spiritual beings.
 This teaching is found in sefer “Chofetz Chaim”, volume 1, klal 8, sif 14, and in volume 2, in klal 7, sif 5. In sefer “Chofetz Chaim”, we learn that when a person rebukes another family member against speaking Lashon HaRa or Rechilus, it should be done by speaking softly. The Chofetz Chaim also points out that a person who is capable of stopping such forbidden speech spoken by members of their household are held accountable in Heaven for such lack of action (Shabbos, 54b). See in the Chofetz Chaim for a further discussion of this matter.