ואדרבה, העצבות היא מגסות הרוח
On the contrary, such sadness is due to conceit.
שאינו מכיר מקומו, ועל כן ירע לבבו על שאינו במדרגת צדיק
For he does not know his place, and that is why he is distressed because he has not attained the level of a tzaddik,
שלצדיקים בודאי אין נופלים להם הרהורי שטות כאלו
to whom such foolish thoughts surely do not occur.
כי אילו הי׳ מכיר מקומו, שהוא רחוק מאד ממדרגת צדיק
For were he to recognize his station, that he is very far from the rank of tzaddik,
והלואי היה בינוני ולא רשע כל ימיו אפילו שעה אחת
and would that he be a Beinoni and not a rasha for even a single moment throughout his life (i.e., this is what he should be striving for at present, rather than vainly desiring to be a tzaddik),
הרי זאת היא מדת הבינונים ועבודתם
then surely, this is the due measure of the Beinonim and their task:
לכבוש היצר וההרהור העולה מהלב למוח, ולהסיח דעתו לגמרי ממנו ולדחותו בשתי ידים, כנ״ל
To subdue the evil impulse and the thought that rises from the heart to the mind, and to completely avert his mind from it, repulsing it as it were with both hands, as explained above in ch. 12.
The Alter Rebbe explained there that the evil in the soul of the Beinoni remains vigorous; his task is to prevent it from expressing itself in thought, speech, and action. Thus, he has no control over the occurence of evil thoughts in his mind, but only over his acceptance or rejection of these thoughts.