In the Sifri, Chazal glean from here that even if the murderer were to take even one step outside of the techum, perimeter, of the City of Refuge, the laws pertaining to the City of Refuge no longer protect his life. In other words, he takes his life in his own hands. The Gerrer Rebbe, z.l., the Imrei Emes, interpreted this halacha, law, homiletically. When a person experiences difficult periods in his life, the only way to deal with the challenges to one’s faith that often accompany such ordeals is to plant both feet within the confines of the bais ha’medrash and study Torah. Only through the guidance and support of the Torah can one triumph over adversity and challenge. The yetzer hara, evil inclination, is very successful in bringing us to sin – especially when we are beset with weakness resulting from an ordeal, a bad experience, a disaster or overexposure to contemporary society. There can be no concessions whatsoever to the yetzer hara. One cannot have one foot within the bais hamedrash and the other cavorting with the yetzer hara and its agents. When one ensconces himself in a Torah environment, eschewing the outside world, then the Torah study and close relationship with friends in the proper environment can help him to overcome the blandishments of the yetzer hara. If we give him one leg, one step outside the perimeter, however, he will grab the rest of our body.
