Guarding the Tongue
First Section – The Gate of Memory – שער הזכירה
This chapter provides the explanation why the Torah is so strict regarding this sin [of forbidden speech]
Behold, in the opening of sefer Chofetz Chaim we have explained [and enumerated] the many negative and positive commandments that one is accustomed to transgress as a result of this bitter sin [of Lashon HaRa], such [not being the case with] any of the other transgressions in the Torah. The adoption of the simple meaning of the pasuk is [therefore] very fitting “Who is the man [who desires life],” “guard [your tongue from evil],” “distance yourself from evil [and do good]”. [By noting “guarding one’s tongue from evil” and “distance yourself from evil”,] King David, Alav HaShalom, wanted to hint to us in a general manner that we should guard ourselves from the sins between man and his fellow as well as from the sins between man and G-d. [Regarding] the grouping of sins between man and his fellow, King David, Alav HaShalom, advised the person who desires life to guard his tongue from evil in all of its specifics, and thereby he will be careful in all [of the sins between man and his fellow].
It is obvious that once one is careful to refrain from sins involving [the attribute of] speech, [the individual will [then] eventually reach the point where he refrains from all sins between man and his fellow. The individual will eventually refrain from all sins between man and his fellow, for when one avoids evils of the tongue, to] never speak derisively about his fellow, observing all of the laws of proper speech, even when [his speaking] would not cause damage to his fellow, he will definitely be careful to avoid robbery, theft, and all other sins [committed] between man and his fellow. [In order for one’s proper speech to lead to observance of all of the mitzvos between man and his fellow, one must be careful to observe all the laws of speech, such as] avoid speaking against his fellow if it would cause [the victim] to lose his livelihood, [cause him] embarrassment, [or] strengthen a dispute. [Once one follows the laws of proper speech], having accepted upon himself not to cause anything unfavorable or shameful to befall his fellow [as a consequence of his improper speech], he will [then] eventually become clean from all sins between man and his fellow.
 Sefer "Chofetz Chaim" is the Chofetz Chaim’s work published together with "Shmiras HaLashon" that details the laws of Lashon HaRa. Immediately following his introduction, sefer "Chofetz Chaim" includes, an opening, one chapter of which enumerates all of the negative commandments related to Lashon HaRa, another which lists all of the positive commandments related to Lashon HaRa, and a third chapter which lists the curses that relate to the sin of speaking Lashon HaRa.
 “Alav HaShalom” means "The Peace is upon him", "Shalom" referring to HaShem. This phrase is used in reference to someone who is no longer alive.
 This is discussed in the introduction to sefer "Chofetz Chaim".