How to overcome a lust for the permitted:
[Is it truly that simple to get rid of one’s desire for the permitted pleasures, by simply learning Torah and performing Mitzvah’s? Many people do so and still have a lust for the permitted. Hence, the Alter Rebbe explains this matter a bit deeper:] It is not the mere performance of Mitzvah’s that melts away the lust for the permitted, but rather also the contemplation of the aspect of Moshe which is Daas. A person should contemplate the fact that he indeed is one with G-d. Now, our sages teach us that a person does not transgress a sin unless a spirit of insanity enters into him. This is because no Jew, even of the lowest level, desires to remove the yoke of heaven from him, and hence even he is willing to give up his life for the sanctity of G-d’s name and no contemplation is required prior to doing so. The mere fact that he knows if he contains a portion of G-d within him suffices for him to give up his life. Now, whenever a person thinks or speaks of material matters that are not relevant for service of G-d he separates himself from this oneness with G-d. There is no Jew who would actually desire this, just as no father would agree for his son to be taken away from him. This then is the meaning of the command “sanctify yourself with what is permitted to you,” as the “you” here is referring to the animal soul, as indeed to the G-dly soul it is forbidden being that it separates one from his attachment to G-d. Contemplating this concept will assist one in overcoming his passion for the permitted.