And you should select from the entire nation men of valor, who fear Hashem, men of truth, who despise profit, and place them upon the nation as ministers of the thousands, ministers of the hundreds, ministers of the fifties, and ministers of the tens. And they will judge the nation at all times. Any great matter they will bring to you. All minor matters they will judge. Your burden will be lightened and they will bear it with you. (Sefer Shemot 18:21-22)
1. Yitro’s advice and Moshe’s response
Bnai Yisrael came to Mt. Sinai. There, Yitro, Moshe's father-in-law, joins the nation. Yitro observes that Moshe was overwhelmed by his leadership responsibilities. Yitro asks Moshe to explain his various responsibilities. Moshe replies that he has three basic tasks. First, the people come to him to seek Hashem. Second, he judges between the people. Third, he reveals to the nation the laws of Hashem. The first set of passages above describes Yitro’s concern and Moshe’s response.
The second set of passages above describes the solution to which Moshe and Yitro agreed. It is immediately evident from these passages that the solution adopted by Moshe and Yitro was not consistent with the dilemma that Yitro described. Moshe outlined to Yitro three areas of leadership responsibility in which he was engaged. The ministers were to be assigned only one of these areas. They would share with Moshe the responsibility for judging the people. Why were they excluded from the other two roles described by Moshe?
2. Moshe’s leadership responsibilities
We need to better understand these three areas in order to answer this question. Rav Yitzchak Zev Soloveitchik Zt”l explains each of Moshe's responsibilities. Moshe explained that the people came to Moshe to seek Hashem. What function was Moshe describing? Moshe was the greatest of the prophets. The people came to Moshe to ask for guidance from Hashem. Moshe also prayed to Hashem for the nation.
The second function described by Moshe was that he judged the people. Moshe resolved legal disputes. In any society there are inevitable disagreements. The courts provide a peaceful means of resolution. Moshe was the judge and arbitrator of all legal disputes.
Third, Moshe revealed the law of the people. Moshe received the Torah from Hashem. He then delivered and taught this revealed truth to Bnai Yisrael.
3. Only one of Moshe’s responsibilities could be shared
We can now understand Yitro's advice. He understood that Moshe was unique. He was Hashem's prophet. Moshe had two functions as a prophet. First, Moshe had a unique degree of prophetic access to Hashem. No other person could fulfill Moshe’s role of petitioning Hashem on behalf of the people. Second, Moshe, as the greatest prophet, was charged with the responsibility of transmitting the Torah and teaching it to the nation. The leadership responsibilities associated with Moshe's role as prophet could not be transferred to ministers. In these areas the ministers could not assist Moshe.
However, Moshe was also a judge and arbitrator. This is not a function related to prophesy. Here, the ministers could offer assistance. They could share the responsibility of judging the nation.
4. Moshe sat and the nation stood before him
Rav Soloveitchik offers a simple proof to his explanation. The proof is based on our pasuk. Yitro noted that Moshe sat and the nation stood before him. This was the situation Yitro sought to end. Which function or functions was Moshe performing while he sat and the nation stood before him?
Yitro could not have been describing Moshe in the process of seeking prophecy. The prophet would not sit while he appealed to the creator! Also, Yitro was not describing Moshe engaged in instructing the nation. While instructing the nation Moshe did not sit with the nation standing before him. This is evident from Rashi's comments on Tractate Eruvin. Rashi explains that when Moshe expounded the Torah, the listeners sat before him.
However, in the court the judge sits. The litigants stand before the judge. This indicates that Yitro observed Moshe judging the people. He understood that Moshe's functions, as a prophet could not be transferred. It was the function of judging that he suggested Moshe share with others.
Our Individual Relationships with Hashem
And Hashem said to him, "Descend and then ascend – you and Aharon with you. And the Kohanim and the nation should not violate the boundary lest He send destruction among them. (Shemot 19:24)
1. The boundaries surrounding Sinai
Hashem's influence descends upon Sinai. Boundaries are set surrounding the mountain. The people are not permitted to approach the mountain beyond these boundaries. Hashem commands Moshe to remind the people that these boundaries cannot be violated. If this injunction is ignored, they will be severely punished.
Rashi explains that Moshe was permitted to ascend to the highest point on the mountain. Aharon could accompany him during most of his ascent. The Kohanim were allowed to ascend to a lower point. The rest of the nation was forbidden from approaching Sinai.
What was the meaning of the boundaries? Why were these various individuals and groups permitted to ascend to different levels of the mountain?
2. Understanding of Hashem is in proportion to one’s development
Maimonides explains that we cannot achieve complete understanding of Hashem. Our material nature limits our ability. We can never completely overcome this limit. However, we can attain some understanding of Hashem. The level of comprehension we can acquire varies. This comprehension varies directly with one's intellectual and spiritual level. Moshe reached the highest possible human development. He achieved a correspondingly profound level of understanding of the Divine nature.
Maimonides seems to suggest that this concept is represented by the various boundaries. Ascending the mountain represents attaining understanding of Hashem. Moshe could climb to the highest point on the mountain. This symbolizes the unique understanding he achieved of Hashem. Aharon was not as spiritually and intellectually developed as Moshe. He could not attain the same profound comprehension. This is represented by the prohibition against accompanying Moshe to the top of the mountain. The Kohanim and the nation were less intellectually and spiritually developed. They were assigned boundaries corresponding with their levels. Their boundaries represent the levels of understanding attainable.
3. The danger of ascending beyond the proper boundary
Hashem warns each group against trespassing beyond its assigned border. The message in this admonition is that every person must recognize his personal limitation. Passing beyond one's boundary represents striving for a level of understanding beyond one's ability. This will result in disaster. The individual who overreaches will not properly understand the Divine essence. Instead, this individual will develop a flawed conception. In order to avoid false conclusion, regarding Hashem, each person must respect personal limitations.
 Rabbaynu Shlomo ben Yitzchak (Rashi), Commentary on the Talmud, Mesechet Eruvin 54b.
 Rabbaynu Moshe ben Maimon (Rambam / Maimonides) Mishne Torah, Hilchot Sanhedrin 21:3.
 Rav Yitzchak Zev Soloveitchik, Chidushai MaRan RIZ HaLeyve on the Torah, Parshat Yitro.
 Rabbaynu Shlomo ben Yitzchak (Rashi), Commentary on Sefer Shemot 19:24.
 Rabbaynu Moshe ben Maimon (Rambam / Maimonides) Moreh Nevuchim, volume 1, chapter 5.