While the term בחירה denotes mere freedom of will in both the physical and spiritual sense, the word רשות portray's man's power to combat evil. It connotes man's capacity and fortitude to defeat his evil inclination. Moreover, while the word בחירה implies that each option is equally accessible, requiring an identical exertion of effort, the term רשות signifies heroic struggle. Although the sinner possesses the potential to overcome evil, he must first engage in a perilous and protracted battle. If the Torah were to have described the phenomenon of רשות, as opposed to בחירה, it would not have described it as accessible, as being neither remote nor distant לא נפלאת היא ממך ולא רחוקה היא. On the contrary, it would have declared that the pursuit of teshuva רחוקה ממך היא, is very remote from you. It is extremely difficult for a person to harness his energies and overcome his natural inclinations. His entire personality rebels against this. Unlike בחירה which presumes accessibility, the word רשות signifies inaccessibility, something which is difficult to achieve בשמים היא. To alter radically one's personality is very arduous.
Nowadays, it can be very difficult to observe Shabbos. Becoming observant is not an obvious option. One must sacrifice both monetarily and socially, in order to observe the Shabbos properly. Often, one faces ridicule and scoffery from the non-observant. The same obstacles are encountered when educating children in yeshivas, as opposed to secular schools. בשמים היא - raising children properly, teaching them to be G-d-fearing and observant requires intense fortitude. רשות presupposes a decision which runs contrary to one's self interest, one which can be financially and socially ruinous. Nonetheless, יש לך רשות each person has been granted the capacity to conquer רע and achieve טוב. Though perilous and fraught with risk, man possesses the fortitude to renounce evil and adopt a righteous lifestyle."
Rabbi Joseph B. Soloveitchik, Noraos HaRav, Vol. 16, p. 18