I heard that the more we listen to our Yetzer Hara, the stronger it grows. Is the flip side true? That is, the more we listen to our Yetzer Hatov, does it grow stronger?
I asked my Rav, who is a big ba'al chassidus, and he confirmed that yes, it is the same.
These ideas are connected to Avot 4:2
שֶׁמִּצְוָה גּוֹרֶרֶת מִצְוָה, וַעֲבֵרָה גוֹרֶרֶת עֲבֵרָה For one commandment leads to another commandment, and transgression leads to another transgression
As you can see, the identical logic is applied to both of the above.
[For those interested, I did make sure that this idea matched up with Chassidus. It does. According to Chassidus, the yeitzer hara is connected to the emotions of the animal soul, and the yeitzer hatov is connected to the emotions of the Divine soul. So the question is - can the Divine soul improve? The answer is YES. The Divine soul isn't just here to mentor the animal soul, it gains from the experience. For example, in Tanya it says the Divine soul experiences a yearning for Hashem. My Rav told me that this yearning can increase, aliya tzorech yerida
E.g. see Or HaTorah, Tehillim 159, and this amazing article by R Tzvi Freeman: https://www.chabad.org/library/article_cdo/aid/80970/jewish/Nefesh-HaBahamis-Animal-Soul-Nefesh-HoElokis-G-dly-Soul.htm
Now, although the Nefesh HaBahamis is pareve, not bad, not good, the desire to overcome obstacles contrary to Torah is of course not good. Born from the Nefesh HaBahamis is the yetzer hora (Evil Inclination). It is a fundamental cornerstone of Torah that every Jew (apart from very special people discussed later) has a yetzer hora. The yetzer hora means literally an inclination for bad. What does “ bad ” mean? “ Bad ” means contrary to Torah and mitzvos. Every Jew has a yetzer hora according to the strength of his Nefesh HaBahamis. The Nefesh HaBahamis is strong in everybody because they are born with a Nefesh HaBahamis. The Nefesh HoElokis requires cultivation. The yetzer hora will be as strong as a man is at any point of time in his life. The Nefesh HoElokis of a Jew spawns the yetzer tov (Good Inclination), the desire to do good. What does “ good ” mean? “ Good ” means learning Torah and doing mitzvos. Every Jew has a yetzer tov, part of the Nefesh HoElokis.
(bold mine). Note: It almost sounds like he is saying that the yeitzer hara doesn't get stronger! Perhaps the degree to which you weaken/strengthen your yeitzer hatov and/or your nefesh habahamis is what impacts the practical strength of the yeitzer hara]
An indirect answer....
Rav Avraham Pam zt"l, the Rosh Yeshiva of Torah Vodaas writes in his sefer Atarah Lamelech p.165 in a chapter entitled "הצלחה בתורה" the following:
הגאון החסיד ר' אברהם מסוכטשוב בהקדמתו ל"אגלי טל" כותב: עיקר מצות לימוד התורה להיות שש ושמח ומתענג בלמודו ואז דברי תורה נבלעין בדמו, ומאחר שנהנה מד"ת הוא נעשה דבוק לתורה, ובזוה"ק דבין יצה"ט ובין יצה"ר אין מתגדלין אלא מתוך שמחה. יצה"ט מתגדל מתוך שמחה של תורה, עכ"ל
The Gaon and Chossid, Rav Avraham from Sokatchov in the introduction to "Iglei Tal" (5 lines up from the wide lines) writes: "The main mitzvah of learning Torah is to be glad and happy and to enjoy his learning, and then the words of Torah will be absorbed into his blood, and once he benefits from the words of Torah he will cling to Torah, and in the Zohar HaKadosh (it states that) both the good and evil inclination grows when in a state of happiness. The good inclination (yetzer hatov) grows from a happiness of Torah".
So, there are means to help assist in the growth of both Yetzarim. Specifically, gaining a state of happiness in Torah learning helps to grow the yetzer tov.
Absolutely. The classic Mussar work Cheshbon Hanefesh is based upon the slow-but-steady approach to gradually build up and improve your middos one week at a time. Check out Chapter 16 specifically.
Rabbeinu Yonah also makes a similar point in his Yesod Hateshuvah:
וכשישמור עצמו מן העבירות שהיה רגיל בהם וכמה פעמים שבאו לידו ונזהר מהם, לא יירא עוד כי מן השמים יסייעוהו
There's a principle that when "the one rises", "the other one falls" (ref. Rashi, Bereishis 25:23), see also Shaarei Kedusha "because when the one rises, the other falls.". In Berachos 5a, it famously says that "if one succeeds and subdues his evil inclination, excellent, but if he does not succeed in subduing it, he should study Torah". The Torah gives strength to a person, in order that he can subdue his yetzer hara. By means of studying Torah, the yetzer hara weakens, so to speak (ref. Likutei Moharan 1:2:10). When the "good forces" are strengthened, they can subdue the evil forces (refer to here).
The second idea, namely that if we listen more to our yetzer hara, it becomes stronger and stronger, can be found in a Gemara in Sukkah 52a:
Apropos the evil inclination and the battle against it, the Gemara cites that which Rav Asi said: Initially, when it begins to entice someone, the evil inclination is like a strand of a spider’s web [bukhya]; and ultimately it is like the thick ropes of a wagon, as it is stated: “Woe unto them that draw iniquity with cords of vanity, and sin as if it were with a wagon rope” (Isaiah 5:18).
Initially, the enticement is almost imperceptible, like a thin strand; however, after one sins, it is like wagon ropes tied tightly around him.
The Gemara in Berachos 5a states that we must incite our good inclination against our bad inclination:
Rabbi Levi bar Ḥama said that Rabbi Shimon ben Lakish said: One should always incite his good inclination against his evil inclination, i.e., that one must constantly struggle so that his evil inclination does not lead him to transgression, as it is stated: "Tremble, and do not sin."
In this article, the commentary Ein Ayah is quoted saying:
In general, the yetzer hara is more awake and ready to act than the yetzer hatov. Therefore [the gemara says that] one should agitate the yetzer hatov to wake it up so that it should be ready to act and to take control over the yetzer hara.
In Sefer Chasidim (155:1) it is explained that a man's good inclination, e.g. the yetzer hatov, can overpower him to do good. Just as the evil inclination, e.g. the yetzer hara can overpower a person to do something not good, G-d forbid, the yetzer hatov can be used to "push aside" the yetzer hara so to speak.
In Likutei Moharan, there's mention of the growth of the yetzer hatov, and the weakening the growth brings to the yetzer hara.