We are currently in weeks that are known as the Shovavim, which is a word from a pasuk שׁוּבוּ בָּנִים שׁוֹבָבִים/Return wayward children. These weeks have that name based on the parshiot we read on Shabbat:
שמות וארא בא בשלח יתרו משפטים
The first letter of each word says spells שובבים /Shovavim, and therefore it's a time of teshuva, and he great rabbis of Kabbala tell us that it’s specifically a time of teshuva in the areas of self-control, such as looking at things that are inappropriate and the like. Durg these weeks, there are people that say extra tehilim, there are people that fast and many other such activities.
The great Mashgiach, Rav Don Segal asked his teacher Rav Yehezkiel Levenstein what one should be doing during the weeks of Shovavim, and he answered, “Work on Emuna, work on your faith.”
He proved it because Shovavim are the Parashiot of Yetziat Mitzrayim.
Obviously, these weeks weren’t just chosen because they spell the acronym Shovavim. They were chosen because of the message of those parshiot, which is Emuna. But Rav Haskel did not explain why working on Emuna helps in areas of self-control.
Rav Don Segal, his student, explained that when a person takes a forbidden desire, he basically wants to enjoy this world, and deep down, he thinks that he's in control of his life and enjoyment.
So, if he wants to eat something that tastes good, even though it might not have the best Hashgacha(or any other break in self-control, whatever it may be), he thinks, ‘I'm going to enjoy something that I can control.’ But if he'd realize that all of the pleasures of the world are decided by Hashem, then he’d know that whatever he controls himself from, he will eventually get back later and better. He can’t gain now by taking an illegal pleasure; he would rather get it later in a legal pleasure.
The Steipler writes in a letter of Hizuk in his Sefer Kryna D’igreta (volume 1 letter 109) that a person has to know that when he controls himself and withstands a test, beside a great kiddush Hashem, and beside the great zechut he has, in this world, he will see the deliciousness in the long run.
In the words of the great Steipler, “Any pleasure that a person holds back from, in honor of Hashem, will be paid back to him someplace else ,in a permissible way.”
He goes on to say that this is well known, that people that control themselves, in the long run get it back. We actually find this in a Mishna in Pirkei Avot.
‘What is the loss of a mitzvah, and what's the benefit?’ There are always loss/gain calculations. Rebbenu Yona explains that when a person says, “How can I do this mitzvah,” or “How can I control myself from this avera? I'm going to lose out.” You should tell yourself, ‘There's a great reward, double or 10 times or a thousand times greater than the loss when I control myself, and therefore I will not lose out.’
Furthermore, the GRA writes in the sefer Aderet Eliyahu (Bereshit 2,9) “Anything that comes to the man of desire, after all his hard work in a forbidden area, comes to the simple people, in the right way, without hard work.”
Additionally, the Sefer Hasidim writes in chapter 155, “God gives those that love Him, their heart's desires in the future- great pleasures, greater than all of the forbidden pleasures that a person has.”
This is important to know. People plan winter vacations, and they take measures to be in more kosher situations. Sometimes it's not as fun or enjoyable, seemingly, as the not-so-kosher approach. But you have to know, and your Emuna has to tell you, that you will enjoy more in the long run in any area.
For a simple example, imagine someone who eats in an establishment doesn't have the best Hashgacha, because it has such a wonderful menu. It looks like he's enjoying and the fellow that's refraining is losing out. But who knows? In years to come, one of them will have a lactose intolerance and he won’t be able to eat anything and the other one won't. We don't know. We can't measure. But we have to believe that Hashem is fair, and that whenever we control ourselves, it pays off.
That's the Emuna that's necessary for self-control.
Have a wonderful day.