What is the significance of the word "v'Yaradti"? Why does the Torah insert it?
Rashi: This is actually one of the ten places where the Torah records that Hashem came down to earth. 1
Da'as Zekenim: This teaches that this day was dear to Hashem like the day of Matan Torah. Also there it says "va'Yered" (Shemos 19:20).
See Sifsei Chachamim.
What are the implications of the word "Vedibarti Imach"?
Rashi: It implies that Hashem would speak specifically to Moshe and not to the elders. 1
What is the meaning of "v'Atzalti Min ha'Ru'ach Asher Alecha"?
Rashi: It means that Hashem will increase some of the spirit that is on Moshe and place it upon them. 1
Rashi (in Bereishis 27:36): It means that Hashem will separate (siphon off) some of the spirit of Moshe and place it on the elders.
Rashi: Like a lamp from which one takes a light to kindle another lamp, which loses nothing of its own light.
What is the Torah telling us here? Why does the Pasuk not inform us as to what Hashem told Moshe?
Ramban: The Torah is teaching us here that Hashem did not appear to the elders at all, and that they only knew of the prophecy via what He told Moshe. 1
Ramban: In other words, the Atzilus was synonymous with Hashem speaking with Moshe, as indicated in Pasuk 28. See also Ba'al ha'Turim.
What does "v'Samti Aleihem" tell us about Moshe Rabeinu?
Rashi: It teaches us that he lost nothing of his own spirit in the process.
What are the implications of "Venas'u Itach b'Masa ha'Am"?
Rashi: Moshe was to make their appointment conditional upon their acceptance to deal with the problems of Hashem's children. 1
Ramban: It implied that throughout their sojourn in the desert, the elders were aware of everything that Hashem spoke to Moshe concerning communal matters. Consequently, whenever Moshe had a Divine message to convey, they had already prophesied it and passed it on to the members of their respective tribes. 2
Why did Hashem see fit to conclude "v'Lo Sisa Atah Levadecha"?
Rashi: Hashem was informing Moshe that this was the reply to his complaint in Pasuk 14.
Ramban: Refer to 11:17:6:2*.
Why did Hashem give to them specifically from Moshe's Ru'ach?
Bechor Shor: It was so they will be secondary to Moshe.
Hadar Zekenim (28): Really, he gave to them from His Ru'ach, just it was a Ru'ach of patience, like Moshe had.
Da'as Zekenim, Chizkuni: I (Hashem) gave to you (Moshe) knowledge and Ru'ach to lead them, and you said 'I cannot do so alone.' They will receive from your Ru'ach!