הלכה על אבות 4:2

The root of this commandment is revealed, as through it a person is protected from sinning against God all his days. This commandment is really a fundamental principle in the religion, as evil thoughts are the progenitors of impurities, and the actions are their descendants. And if a person dies before having children, there is no record of the progeny; so it emerges that this prevention is the root that all good comes from. Understand my son, and let it be a jewel in your mouth, that which they, may their memory be blessed, said (Avot 4:2), "One sin leads to another, and one commandment leads to another." As if you allow yourself to fulfill your evil desire one time, you will be drawn after it many times. But if you merit to be 'mighty in the land' and to conquer your evil inclination and close your eyes from seeing evil one time, it will be easier for you to do so many times. As lust pulls the body like wine draws the drinker. Drunkards can never be sated by wine, but they will rather have a great desire for it. And according to [the large quantity that] they have gotten themselves accustomed, the stronger their desire will become. And if only they would drink a cup of water, it would temper the burning fire of [their] desire for wine, and make it pleasant for them. The same is true here: The more a person allows himself to be governed by his desires and to allow them to become habit, the stronger his evil inclination becomes every day. But in his preventing himself from them, he will always be happy with his portion every day; and he will see that 'God made people straight, but they seek out many schemes' for no reason of any point.

And [also] that which they said (Shabbat 49a) that tefillin requires a clean body, and they said in the Gemara, "What is a clean body? That he be careful not to pass gas with them [on]." But the matter is not to say that it requires a body clean of sins or of impurity. As every man, even one impure or a sinner is obligated about the commandment of tefillin, so long as he knows to be careful not to pass gas with them [on]. And maybe from being constant with the commandment of tefillin - as they are a great memory device for a person about his service to the Heavens - he will repent from his evil way and purify himself from all of his filth. And the Sages, may their memory be blessed, obligated us about the commandment of tefillin to educate even the small youths about it, so long as they have arrived to the category [of those] that know to guard them. And from here it can be understood that the opinion of our Rabbis, may their memory be blessed, was that every man should grab onto this commandment and be accustomed to it, since it is a great fundamental, a protection from sin and a strong ladder to climb with to enter into the service of the Creator, blessed be He. And maybe the intention of those that are stringent about the holiness of the commandment, and discourage the hearts of the masses with their words from being involved with it, is good. But in truth, through this, there is the prevention of people from several commandments, and [so] it is a great evil. And [this is] even though I know that those that preach these lessons base themselves on the Talmud Yerushalmi Berakhot 2:3, "About a certain man who deposited a glass with his fellow, and afterwards demanded it [back] from him and [the other] denied [having it]." And the owner of the glass said to him, "'It is not you that I trusted, but that which is on your head that I trusted'" - and their intention is to say that there is a desecration of God's name, to be pious about some commandments and to be evil about others. But this is not my home with God (not how I understand the ways of God); as I know that 'there is no righteous man in the world who does good and never sins,' and nonetheless he is not prevented from being involved with commandments when the good spirit of God clothes him to do the good. As who knows whether maybe he will continue in his good path until the time of his death - and death will come suddenly. And they, may their memory be blessed, have already taught us (Avot 4:2) that "a commandment leads to another commandment" and "the reward for a commandment is another commandment." About all of these things and the good ethics, they, may their memory be blessed, have preceded us and taught us. And those that want to be wise and add upon their words or take away [from them] are not [involved in] wisdom.