As a loyal servant in the presence of his master, I believe we can add an interesting tidbit to the assertion of the Arizal. Upon further scrutiny, it is apparent that the advice proffered by Rabeinu HaKadosh is amazingly consistent with the approach of Yaakov Avinu. Rebbe advised us how to avoid being deceived and led astray from the proper path of action by the yetzer. Yaakov Avinu was also extremely conscious of the fact that the yetzer hara distorts the words of G-d, from good to bad and vice versa. This prompted Yaakov Avinu to pray to HKB”H (ibid. 32, 12): "הצילני נא מיד אחי מיד עשו כי ירא אנכי אותו פן יבוא והכני אם על בנים"—save me, please, from the hand of my brother, from the hand of Eisav; for I fear him lest he come and strike me, mother and children. Rashi explains why Yaakov said both “from the hand of my brother” and “from the hand of Eisav,” which seems redundant. He was expressing the fact that he was not confronting someone acting like a brother but rather Eisav HaRasha.
In Kedushas Levi, the esteemed Rabbi of Berditchev, zy”a, and in Zikaron Zot, the esteemed Chozeh of Lublin, zy”a, explain that Yaakov Avinu was actually praying to HKB”H to be saved from the yetzer hara—alluded to by Eisav. Outwardly, he pretends to be “my brother,” as if he intends to help me serve Hashem. In reality, however, he is secretly plotting to trap me in his web. Consequently, Yaakov says: "כי ירא אנכי אותו"—for I fear him—since it is exceedingly difficult to guard oneself against this type of yetzer—who comes deceitfully, pretending to help a person serve Hashem.
It is worth noting that this understanding comes from our most sacred and exalted sources. For instance, the Orach L’Chaim (Lech Lecha) presents in the name of the Ba’al Shem Tov an interpretation of the following Gemara (Shabbas 75a): "שוחט משום מאי מחייב, רב אמר משום צובע"—what is the “shocheit” guilty of? Rav said it was because of dyeing. According to Tosafos, the Gemara is referring to the “shocheit” of the world. The Orach L’Chaim explains that they are alluding to the yetzer hara who slaughters the entire world by enticing them to commit aveiros.
Along these lines, another Gemara teaches (Succah 52a): "לעתיד לבוא מביאו הקב"ה ליצר הרע ושוחטו" —le’asid la’vo, HKB”H will hold the yetzer hara accountable and slaughter it. This prompts the Gemara to inquire: “What is the ‘shocheit’ (yetzer hara) guilty of? In other words, why is the yetzer hara—the “shocheit of the world”—guilty and deserving of the death penalty le’asid la’vo? After all, wasn’t it created for this purpose—to trap people and persuade them to transgress? To which Rav answers: "משום צובע". Here a play on the word "צובע" is employed. Rather than translating it as “dyeing,” it is translated as “being deceitful” and portraying (coloring) something as something else; it colors the truth. In other words, HKB”H created the yetzer hara initially with a specific purpose. Its job was to tempt mankind openly to commit aveiros—not to conceal its intent or employ deceptive tactics. While this type of yetzer hara is also extremely dangerous, it is still easier for a person to guard himself and withstand a yetzer hara whose intent is overt.
Unfortunately, there is a more dangerous yetzer hara who uses ingenious tactics; hence, it is harder to withstand. It knows that if it approaches a Jew openly to tempt him to commit an aveirah, the Jew will ward it off with disdain. Therefore, it schemes to trap the Jew in its web by disguising the aveirah as a mitzvah. It employs all sorts of persuasive arguments to convince a Jew that he is doing the right thing—that he is actually performing a mitzvah and not an aveirah. Extra caution is required to protect oneself from this type of yetzer hara, since a person might perceive it to be a yetzer tov trying to help him better serve Hashem.
Now, HKB”H created the yetzer hara to function in such a way that it would test man, but he could exercise his freedom of choice and resist committing an obvious aveirah. However, we can describe this yetzer hara as a rogue agent; it betrays HKB”H and chooses to operate in a manner that it was not authorized to operate. It deceives mankind by portraying an aveirah as a mitzvah. Therefore, HKB”H will slaughter it in the future as punishment for its treachery. In the words of Rav above, it deserves to die "משום צובע"—for coloring an aveirah to appear to be a mitzvah. As explained, it was not authorized to function in this manner.
So, it appears that this was also the inquiry of Rabeinu HaKadosh, the “nitzotz” of Yaakov Avinu. He posed the question: “Which is the proper path that a man should choose for himself?” In other words, how can one be sure that he isn’t being tricked by the yetzer into believing that an aveirah is actually a mitzvah? To which Rebbe answers: He should cling to the midah of “Tiferes,” the midah of Yaakov Avinu, to discern whether or not the act in question will be a credit to him and whether or not a tzaddik will approve of this act. In this merit, he will be spared. Just as Yaakov Avinu prayed: “Save me, please, from the hand of my brother, from the hand of Eisav”—so, too, a Jew who follows Rebbe’s advice will be protected from the yetzer hara who pretends to be his brother to help him serve Hashem.
