[In order to successfully attain the attribute of Shmiras HaLashon] all of these [actions] shall be accomplished [one] level [at a time]: From the start, one should accustom himself to not stand amidst a group of people, and to avoid searching for news [related to the goings-on of others]. Next, he should slowly accustom himself to [remove his] desire to listen to any news [that may involve gossip], until eventually, HaShem will Help him [to the extent] that he will [completely] acquire this attribute of Shmiras HaLashon within his nature. [He should make the attribute of Shmiras HaLashon such a part of his nature] that if he were to subsequently see a person who is transgressing the prohibition of Lashon HaRa, or any similarly [forbidden speech], he will be astounded at [such a person], since this matter [of Lashon HaRa will be] foreign to his nature, just as the rest of the [Torah] prohibitions are [foreign] to the entire [nation of] Israel. For, this [matter of making the attribute of Shmiras HaLashon a part of one’s nature] has already been tested in the “furnace of testing”, [it thereby being known that] guarding the tongue from [speaking that which is] evil, and [safeguarding] the ears from hearing forbidden speech, will only be difficult on the person for a few weeks. For, once this [period of time passes], when the people see that this individual refuses to speak and to hear Lashon HaRa and [words of] mockery, as well as the other [types of] forbidden speech, [then] all those who relate [that which is forbidden] will desist from relating to such a person [of] any matter that relates to this prohibition [of forbidden speech. Once he realizes [that relating the forbidden speech] will not make him viewed as honorable and splendorous in the eyes of this man [who desists from hearing forbidden speech], the individual who wishes to relate forbidden speech], will go with this “merchandise” of Lashon HaRa and Rechilus [and take it] to someone who wishes to acquire it, as [the person who shuns forbidden speech] will consider him to be a habitual speaker of Lashon HaRa or [view him to be] a scoffer. [Such a person who seriously works to attain the attribute of Shmiras HaLashon], will practically not even have to guard himself from hearing [forbidden speech], for the habitual speakers of Lashon HaRa, themselves, when they speak of any incident [which is forbidden to relate], will guard themselves from him. If [this person who is known to avoid forbidden speech is found in] close [proximity] to [the speakers of Lashon HaRa], they will not relate [that which is forbidden], for they will fear for themselves, [that] perhaps this listener will “damage” their “merchandise” in the eyes of the other [potential] “buyers”. It will only be difficult for the person in the beginning [of his quest to attain the attribute of Shmiras HaLashon] to truthfully agree [to accept] this matter [of guarding his tongue upon himself], as mentioned earlier. All of this [that we have mentioned above], falls in the category of that which our Sages of Blessed Memory have said in [maseches] Moed Katan (5a), [as follows]: “One who marks off [the proper] path [of Torah that he will follow] in this world, merits and sees the salvation of The Holy One, Blessed is He.”
 The passage in the gemara is as follows:
“Ravina said, “[Those who offer Me an offering upon which he confesses [his sins], will honor Me], and those who place [themselves on the] path [of repentance], I shall show him the salvation of G-d.” (Tehillim: 50; 23) Rabbi Yehoshua ben Levi said, “All those who evaluate their paths [in life] merits and sees the salvation of The Holy One, Blessed is He, as it says, “All those who place [themselves on] the path [of repentance], I shall show him the salvation of G-d.” Do not read [the word] as “v’sam derech” – “and place [themselves on] the path”, rather, [read it] as “v’sham derech arenu b’yeisha E-lohim” – “and [those who] evaluate the course [of their actions], I shall show him the salvation of G-d.””
RaSh”I explains the gemara as follows:
“V’sam” – The person makes a sign which directs him in the path he should follow [in his life].
“V’sham” – “and evaluates” – This refers to someone who evaluates the paths of his life and weighs the reward for performing a mitzvah against the loss involved in its performance and who similarly weighs the reward for performing a sin against the loss for refraining from sinning.