Metzuveh VeOsseh

Masecket Kiddushin (ל"א ע"א) relates a story regarding Rav Yossi. Rav Yossi was blind and therefore possibly exempt from many mitzvot. He used to say that he would throw a big celebration if anyone would prove conclusively that the blind are exempt from the Mitzvot. Rav Yossi held at this point that someone who does the commandments voluntarily is greater than one who is commanded. Once he heard the drash of Chazal that one who is commanded and performs the commandments is greater than one who does so voluntarily, he exclaimed that he would throw a celebration if anyone proved conclusively that the blind are obligated in the mitzvot.

The Rishonim and Achronim all have different takes on why one who is commanded and performs commandments is greater. The tosefot and the ritva (תוס' עבודה זרה דף ג' ע"א, ד"ה "גדול", בריטב"א בקידושין שם) say that the reason is psychological. People have a natural aversion to authority. As soon as one is commanded, they have an immediate desire to assert their own independence and thus they have a greater evil inclination to overcome than those who perform mitzvot voluntarily.

Several other rishonim (ריטב"א בשם הרמב"ן, תוס' הרא"ש, דרשות הר"ן, דרוש השביעי) explain that the advantage of being commanded is that on top of doing an act that is intrinsically good, you are also fulfilling the will of the King. This means that those who are commanded are performing an act that is essential to the functioning of the world. If the act was not essential then it would not have been commanded.

This second explanation in the rishonim fits perfectly with the Maharal’s explanation of the famous midrash in masechet Shabbat (פח ע"א) where Hashem suspends mount Sinai above the heads of the Jewish people and forces them to accept the Torah. The Maharal explains that this is to teach that the Torah is not in the realm of "choice", an addition to natural life. Rather the Torah is an essential component of the world and without it, life can not continue in a normal fashion.