Going the Extra Mile

This explains the Talmudic statement that “he who serves G‑d” refers to one who revises his studies 101 times, while “he who serves Him not” refers to one who revises his studies only 100 times. This is so because in those Talmudic days, it was customary to review each lesson one hundred times. The Talmud illustrates this by the analogy of the market of the donkey drivers. The drivers would charge one zuz for ten parsi (Persian miles), but demanded two zuz for driving 11 parsi, for driving an eleventh mile exceeded their customary practice. Therefore, this 101st revision, which is beyond the normal practice to which the student has been accustomed since his childhood, is equivalent to all the previous one hundred revisions combined. In fact its quality surpasses them in its greater strength and power, so that it is only this one extra revision which entitles the student to be called “he who serves G‑d.” - Rabbi Shneur Zalman of Liadi in Tanya Chapter 15