And he dreamt and behold there was a ladder stationed on earth with its top reaching heaven. And behold angels of Hashem were ascending and descending upon it. (Bereishis 28:12)
Commenting on this posuk, the Medrash Rabbah informs us that the ladder is a symbol of Mount Sinai. A source for this is the fact that the numerical value of both sulam (ladder) and Sinai (Mount Sinai) are the same. The Medrash continues to explain that the angels of Hashem mentioned in the posuk refer to Moshe and Aharon.
Taken at face value, the Medrash could simply be telling us that both Moshe and Aharon were involved in going up Mount Sinai to receive the Torah. This interpretation is difficult, however, because Aharon was not actually fully involved; only Moshe was. Why then does the posuk, according to the Medrash, include Aharon?
Let us suggest a homiletic interpretation of this Medrash. But first we must introduce a few concepts.
Sinai is a symbol of humility. The Gemara (Megilah 29) tells us that Hashem chose to give the Torah on Mount Sinai because it was the lowest of all mountains, i.e., the most humble of all. Going a step further, we are aware that the main characteristic of a ladder is that it has rungs, i.e., levels. By connecting a ladder with humility, we are informed that within humility there are many levels. There is extreme humility that corresponds to the lowest rung and there is less extreme humility, which corresponds to the higher rungs.
With regard to Torah, we must strive for the extreme level of humility. The Gemarah (Taanis 7a) equates Torah with water as written in the posuk: "He who is ever thirsty go to water." (Yeshayah 55:1) The posuk is interpreted as meaning that whoever is thirsty for Hashem should delve into the Torah." The Gemarah goes further to explains that just as water descends to the lowest level, so too Torah can be found only in the humble. We must also, however, understand that although extreme humility is a most honorable trait, it is not always appropriate for every situation. For example, it is not desirable for a king to display extreme signs of humility. A king is not even allowed to be forgiving with his honor. A king, by definition, is higher and thus elevated from his people. The same holds true for Kohanim. By definition, they are elevated above the rest of Klal Yisroel and it is only they who may serve in the Bais Hamikdash.
The posuk (Bamidbar 12:3) informs us that Moshe was the most humble man on the face of the earth. He occupied a lower rung on the ladder of humility than did Aharon his brother. As explained above, Torah demands extreme humility. Therefore, it was precisely because Moshe was the most humble of all that he was the ideal candidate to receive and transmit the Torah. But he was not ideal to lead the Kohanim. As explained above, kehuna requires a level of humility that does exhibit small signs of pride. For this, Aharon was the ideal candidate.
What emerges from the ideas explained above is that both Moshe and Aharon served the leadership position that fit each of them best. Moshe, who embodied the epitome of humility, was chosen to receive and transmit the Torah, whereas Aharon, who embodied the humility of a higher rung, i.e., had a bit of pride, was chosen to lead the Kohanim. Their respective character and positions were thus mutually exclusive.
Now let us return to reinterpret the Medrash.
Yaakov dreamt and he saw a ladder. The Medrash tells us this was Mount Sinai, which we now interpret as symbol of humility. The posuk continues: "it was stationed in the earth but its head reached heaven." This can be interpreted based on a Gemara.(Eruvin 13b) "Whoever lowers himself will be raised by Hashem." The posuk tells us that the character of humility is such that if it "is positioned in the earth," i.e., one humbles himself, eventually "its head reached the heaven," i.e., Hashem will elevate him to greatness. The posuk continues: "Behold he saw that angels of Hashem were ascending and descending upon it." The Medrash tells us that the angels refer to Moshe and Aharon. This can now be interpreted as the reason why Moshe and Aharon's life missions were mutually exclusive. Moshe, who possessed the extreme trait of humility, served as the recipient of Torah. He was thus oleh (rose), i.e., rose to greatness in being the individual chosen to receive the Torah but at the same time he was yoraid (descended), i.e., rejected to serve as the leader of the Kohanim. Conversely, as a result of his station on the ladder of humility, Aharon was oleh (raised) to the position is serving as the leader of the Kohanim but this rung also caused him to be yoraid in his ability to serve as the recipient of the Torah on behalf of the Jewish people.
We learn from this that we must also position ourselves on the ladder of humility. When learning Torah, we must descend to the lowest rung and strive for the extreme level of humility. When acting in the capacity of leader, in whatever form it might be, we must rise a rung or two and display small signs of pride. However, we must never forget to remain positioned on the ladder regardless of the circumstance. Only then will we merit the continuation of the next posuk: "And behold Hashem was standing above him."