There are, according to the famous work of the Rabbeinu Yonah "Shaarei Teshuvah", twenty principles of teshuvah (mentioned in the first chapter). The Rabbeinu Yonah writes that for example, if one of a person's sins is lashon hara (slandering), he should occupy himself with the study of Torah (Shaarei Teshuvah, 1:35).
Rav Dessler, in Michtav Me'Eliyahu (A shortcut to teshuva, p. 115) explains that there are four "shortcuts" to doing teshuva. One of these is Torah-learning. Rav Dessler writes "to drive away the yetzer hara".
However, the Steipler Gaon in his Chayei Olam (end of chapter 13, sv. רדןנננויהונו) writes as follow:
רדןנננויהונו חז"ל שהבא לטהר מסייעין אותו יימא ל"ה נב' אכן לא נקרא בא לטהר אלא אם כן שוקד על התדרה כפי יכלתו ושומר מצוותיה כראוי ונשמר ממפסידיה כגון קריאת ספרי רשעים או התחברות עמהם חס ושלום אבל כשיש בידו לעסוק בתורה ואינו עוסק או מזלול חס ושלום במצוות השם יתברך או שאינו נשמר ממפסידי האמונה אין זה בגדר בא לטהר אלא בא לטמא חס ושלום אשר אמרו עליו פותחין לו חס ושלום והשם יתברך ינוונו במעגלי צדק למען שמו יתברך The sages have promised us: "he who comes to purify himself, merits to be helped from above (Yoma 38b)". However one is not in the category of "he who comes to purify himself" unless he is "shokade" (diligent) in torah (study) according to his ability, and he guards its mitzvos (commandments) properly, and he guards from things that prevent this, such as books of the wicked, or joining with the wicked themselve [...].
The Steipler goes on to explain that if one does not do this (learning Torah), or if one is mezalzel (lax), he is not "one who comes to purify himself", rather "one who comes to defile himself".
Where does this idea come from? Is learning Torah a pre-requisite from doing teshuva at the beginning? Surely, studying Torah is knowing how to act, and thus knowing how not to act. But is a succesful teshuva dependant on it? Why does the Rabbeinu Yonah not write that Torah study is the first principle, or another principle? It seems that what the Steipler is saying, a person should first study Torah, and then he can start teshuva and is guided by Hashem. Is this true? Source-based answers please.
Is teshuvah not, as Rambam puts it, "when a person abandons the sin that he sinned and removes it from his thoughts and commits in his heart that he will not do it again"?