The Jewish people were granted the unique ability to draw down Divine effluence through their performance of Torah and mitzvos. Performing Torah and mitzvos not only benefits the performer (as mentioned above), but also enables the physical objects with which the mitzvos are performed to become vessels for G‑dliness.

The reason why only Jews possess this quality is because of their power of mesirus nefesh, total self-sacrifice. Moshe says to the Jewish people:1 "Not because you were more in number than any people did the L-rd set His love upon you and choose you, for you are least [in number] of all the nations." That is to say, G‑d gave the Jewish people the Torah not because we possess greater intellects or more powerful emotions than the other nations, but because we possess the power of mesirus nefesh.

There are three souls. There is the nefesh hativis the natural soul, also called the animal soul; the nefesh hasichlis or intelligent soul, whose source is Pnai Adam of the Divine Chariot; and the nefesh elokis the divine soul, whose source is Supernal Man, as it is written:2 "And upon the form of the throne, a form with a likeness to man."

Even the first two souls the animal and the intelligent are different in Jews than in other nations. This is especially true of the divine soul, which is truly a part of G‑d above,3 encompassing the intellect and emotion of holiness.

The intellect and emotion of holiness are two levels of the G‑dly soul called nefesh elokis and yetzer tov, respectively. Nefesh elokis refers to the intellect, which is in turn composed of chochmah, binah and daas (wisdom, understanding and knowledge), while yetzer tov refers to the impulse which generates acts of goodness directed toward one's fellow man, and the actual performance of mitzvos.

Still, G‑d did not give Jews Torah and mitzvos on account of our particular powers of intellect or emotion, though they are totally different from those of other nations. Rather, He gave us Torah and mitzvos because "You are the least of nations."

The term "the least" refers to the self-abnegation and mesirus nefesh found only among Jews. Mesirus nefesh is called bitul haratzon nullification of personal desire. For the word nefesh also means desire, for it is written:4 "My nefesh is not to this nation," as Rashi explains.

Mesirus nefesh thus involves the total dedication of one's desire to G‑dliness, above and beyond the comprehension of the individual. This finds expression in the phrase na'aseh v'nishmah, "we shall do and we shall hear," which the Jews uttered at the time the Torah was given. Na'aseh means devoting oneself to G‑dliness, the Infinite One, the Master of desire, with a total renunciation of personal will. The prefacing of na'aseh, "we shall do" to nishmah, "we shall hear" signifies acceptance of the heavenly yoke in order to fulfill all that G‑d will decree. It was due to this mesirus nefesh that G‑d gave the Torah to the Jews.

In summary: G‑d gave Jews the power to perform Torah and mitzvos notwithstanding their difficulty. This power comes from every Jew's divine soul, which he or she possesses in addition to the "natural" and "intellectual" souls. The acceptance of the heavenly yoke was accomplished through the proclamation of "na'aseh v'nishmah."