A saying of the Rebbe Maharash: 'Close your mouth from speaking.'

פעם התאונן חסיד אחד לפני אאזמו״ר מהר״ש (אצל המהר״ש הי׳ רוב החסי­ דים בע״ב מלמדים ישוב׳ניקעס) על עצמו שהוא בעל תחבולות, אין יעדער זאך אין יעדער ענין נעמט ער בערמומית. א״ל אאזמו״ר מהר״ש אז ער זאל פאסטען 6 הונדערט תעניתים אפילו ר״ה ויוהכ״פ. השואל תמה ע״ז. ויאמר לו: וואס מיינסטו, פאסטען הייסט ניט עסען פון נץ החמה ביז צו דער שקיעה, דאם הייסט דארען, תענית איז א עבודה, טראכט אלע טאג 15 מינוט אדעתי׳ דנפשי׳ וועגען זיך, בלום פיך מלדבר ניט מחשבת דא״ח גאד פשוט טראכטען וועגען זיך. כשעברו ב׳ שנים נשתנה באו״א לגמרי, וכשסיפר לי אאמו״ר המעשה הזאת אמר לי: ניט נאר ער איז נשתנה געווארען אין כחות

Translation:
Once, a Chassid complained to my grandfather the Admor Maharash (among whom most Chassidim were teaching the farmers) about his own cunning nature, always employing craftiness in every matter and issue. The Admor Maharash instructed him to fast 600 fasts, even on Rosh Hashanah and Yom Kippur. The questioner was astonished by this. The Admor Maharash explained: What do you think? Fasting does not mean merely refraining from eating from sunrise to sunset; rather, it means enduring. A fast is a form of service to Hashem; consider spending 15 minutes each day in contemplative self-examination, keeping your mouth from speaking, refraining from idle thoughts, simply reflecting deeply about yourself. After two years, the individual had completely transformed. When my father (the Rashab) told me this story, he said: Not only did he change in his abilities...

Explanation:
This narrative underscores a lesson from the Admor Maharash, a prominent Chabad leader in the 19th century, concerning the spiritual and moral development of a person. The Chassid, described as "cunning" and "crafty," receives guidance not in the typical form of punishment or repentance but as a deep meditative discipline. Maharash redefines fasting as a form of "endurance" and "service to Hashem," extending beyond simple abstinence from food. It involves a daily dedication to profound personal reflection, suggesting that true transformation emerges from within and necessitates continuous effort and introspection. This approach led to a remarkable transformation in the Chassid, illustrating the effectiveness of sustained spiritual practice.