We spoke earlier about the power of Torah study to eliminate the power of tumah.
The Noda BiYehudah emphasizes that the benefit of studying Torah is realized only when one is totally immersed in his learning. In his words:
If one is constantly thinking about Torah, there is no room for thoughts of ervah to take hold. The Gemara therefore writes that if one succumbed and saw something improper he should “involve” himself in Torah study, as it is written, “say in your heart” - i.e., it does not suffice to learn Torah superficially. Rather he must study with intense depth, as it is written, “in your heart ...”
R’ Michel Yehudah Lefkowitz makes this same point:
Sadly, experience shows that some people who study Torah nevertheless struggle with their yetzer hara and are swayed by it.
Why? Why did their Torah not save them? The answer is ... that it is not sufficient to merely learn Torah. A person must focus all his mental powers into Torah so that it completely fills his heart and mind, without leaving room for other thoughts.
R’ Yisrael Salanter (Iggeres HaMussar) also stresses that "Torah therapy" requires one to delve deeply in Torah, but adds that learning Torah is particularly effective when one studies the halachos that pertain specifically to the area in which he is being challenged:
When using Torah as therapy for the maladies of the yetzer hara, it is critical that one study energetically and with great depth the laws of that specific sin with all its details.
He notes that most people will never eat bread without washing their hands first even when hungry, but people speak lashon hara freely - though the punishment for the latter sin is clearly much more stringent. He explains that this is simply a matter of training and doing what you are used to. In order that avoiding the sin should become second nature, he suggests studying Torah (particularly the relevant laws) and training oneself through repetition.