The Mitzvah of shiluach ha'kan (sending away the mother bird before taking her young) is described by the Torah in Parshas Ki Seitzei: "If a bird's nest happens to be before you on the way, in a tree or on the ground, and the mother is sitting on the chicks or eggs, do not take the mother along with the young. Send away the mother and then take the young" (Devarim 22, 6-7).
The Gemara (Chullin 139b) asks, since the pasuk stresses that the nest was found on the ground, if one finds a nest on top of a person's head, is he also obligated to fulfill the mitzvah of shiluach hakan? The Gemara answers that he is obligated, since we find another pasuk (Shmuel II 15, 32) which states, "And ground upon his head." Rashi explains that since the Torah chose the word "ground" as opposed to "dirt", we can deduce that despite the fact that the dirt was detached from the ground it did not lose its identity, because while resting upon a person it is still considered attached to the ground. If so, it must be that the human being himself is considered ground, and therefore, the dirt upon his head is considered as if it still lies upon the ground!
This fascinating Gemara gets even more interesting. The very next Gemara asks, "Where does the Torah allude to Moshe [even before he was born]? 'Since he is but flesh' (in Hashem's declaration that he would destroy the world with a flood)." Rashi explains that "beshegam" (since he is but) has the same numerical value as Moshe. Moreover, the generation of the flood was given 120 years to repent, and Moshe lived to 120.
Rav Wolbe (Da'as Shlom Geulah pg. 187) explains the connection between the two Gemaras. The first Gemara stresses the lowliness of man: even after being created he still remains "a clump of ground." The second Gemara stresses the exact opposite: the greatness of man. Despite the fact that he "is but flesh" he has the ability to rise to the level of the angels as Moshe accomplished. His origin is lowly, but his potential is unlimited!
This idea sheds light on the subsequent Gemara as well. "Where does the Torah allude to Haman? Is it from the tree [that I told you not to eat from that you ate]" (Bereishis 3, 11)? The tree of knowledge was the root of all evil. However, Haman succeeded in taking evil to a whole different level. Because a single person failed to bow down to him, he schemed to annihilate an entire nation! Once again we perceive the unlimited ability of man - only this time it was harnessed toward evil.
"Where is Mordechai hinted to in the Torah? Mara Dachia" (The Targum's translation of Mor Dror, the first of the spices used in the incense. Shemos 30, 23). The incense was burned in privacy while no one was watching. This was the attribute of Mordechai who personified the middah of tznius - doing what is right without fanfare. Esther also exemplified the middah of tznius, since after she became queen, she did not reveal her nationality.
Rav Wolbe adds that there is yet another common denominator between Mordechai and the incense. The smoke caused by the burning of the incense would rise like a pillar without spreading to the sides. So too, Mordechai stood ramrod straight and did not bow or bend to Haman and the evil he espoused. It was these two traits - tznius and an unswerving adherence to the Torah's standards - that affected the miracle of Purim.
The lesson to be learned is clear: Man's ability is unlimited. Harnessing our awesome potential toward the service of Hashem, not only brings us closer to Him; it also has the ability to bring redemption to His entire Nation!