Slaying The Inner Enticer
בפרשה של המסית צריך כל אדם להכין עצמו למצוה זו כי הוא ענין נכבד להיות מתפעל האדם להתהפך כרגע לשונא ממש ע"י ההסתה לקיים לא תחמול ולא תכסה
In the parsha of the mesis (the one who entices a person to idolatry), every person must prepare himself for this mitzvah, for it is a weighty matter that a person be so stirred as to transform himself in an instant into an absolute enemy of the enticer, through that enticement, in order to fulfill "you shall not pity nor conceal" (Devarim 13:9).
The Torah's section about the mesis teaches that one must ready himself to feel genuine hatred toward whoever entices him away from Hashem, fulfilling the command to neither pity nor cover for him.
ומכ"ש שזה קאי על היצה"ר וסט"א שהוא המסית ומדיח
And all the more so does this apply to the yetzer hara and the Sitra Achra (the side of impurity), which is the true enticer and seducer.
This applies even more so to the yetzer hara and the Sitra Achra, which are the real force enticing a person to sin.
ואם נעשה האדם שונא ממש ע"י הסתה
And if a person becomes an absolute enemy through that enticement,
When a person responds to the enticement by turning into a true enemy of the yetzer hara,
יוכל להרוג אותו
he is able to slay it.
he gains the ability to destroy it.
כמ"ש אח"כ כי הרוג תהרגנו ע"י השנאה כנ"ל
As it is written afterward, "for you shall surely kill him" (Devarim 13:10) — by means of the hatred, as explained above.
The pasuk's words "you shall surely kill him" come about precisely through this hatred toward the enticer.
הרוג הוא בפרטות מה שמסית לו
"You shall kill" (harog) refers in particular to that specific matter in which it entices him,
The first word "harog" speaks of the specific area in which the yetzer hara is tempting him at that moment.
ותהרגנו הוא לגמרי שע"י נסיון אחד זוכה להתקדש בכל
while "you shall surely kill him" (tahargenu) means completely — that through a single nisayon (test) a person merits to become sanctified in everything.
The added word "tahargenu" hints that overcoming even one test elevates a person to be fully sanctified across the board.
ועוד ידך תהי' כו' ויד כל העם באחרונה
And further, "your hand shall be... and the hand of all the people at the last" (Devarim 13:10).
The pasuk continues that the hand of the one tested, and then the hand of all the people, share in this act.
פי' כמ"ש כל ישראל ערבים זה בזה
The explanation is as it is stated, that all of Bnei Yisrael are areivim (responsible sureties) one for another.
This is because all of Bnei Yisrael stand as guarantors for one another, bound together as one.
א"כ מכ"ש שמה שגובר א' והורג היצה"ר שבו מזכה לכל ישראל שלא יהי' עוד כח להיצה"ר באותו דבר כמו מקודם
If so, all the more so does that which one person prevails and slays the yetzer hara within himself bring merit to all of Bnei Yisrael, so that the yetzer hara will no longer have any power in that particular matter as it did before.
Therefore, when a single Jew conquers and slays his own yetzer hara, he brings merit to the entire Bnei Yisrael, draining the yetzer hara's power in that area for everyone.
וזה עצמו צריך להוסיף כח לכל עובד ה' במה שיודע שע"י תגבורת שלו יחליש כח היצה"ר נגד כל ישראל כפי הכח של הנסיון:
And this very thing must add strength to every servant of Hashem, in knowing that through his own prevailing he weakens the power of the yetzer hara against all of Bnei Yisrael, in accordance with the strength of the nisayon.
This realization should strengthen every servant of Hashem: his personal victory weakens the yetzer hara's grip on all of Bnei Yisrael, in proportion to the difficulty of the test he overcame.
Summary: The Sfas Emes draws from the parsha of the mesis a model for the inner avodah of every Jew. Just as the Torah demands that a person turn into an outright enemy of one who entices him to idolatry, so too must one cultivate genuine hatred toward the yetzer hara and the Sitra Achra, the true enticer, in order to be able to slay it. He reads the pasuk's doubled language "harog tahargenu" to mean that conquering even a single nisayon in one specific area sanctifies a person completely. Finally, because all of Bnei Yisrael are areivim one for another, one individual's victory over his yetzer hara drains its power against the whole nation in that matter. This awareness should give added strength to every servant of Hashem, knowing his personal struggle uplifts all of Bnei Yisrael.