What did Moshe mean when he instructed the elders "Sh'vu lanu ba'Zeh!"?
Rashi: As he left the camp, he instructed them to remain in the camp, in order to litigate any disputes, should the need arise. 1
Ramban #1: He was not instructing them to remain at the foot of the mountain 2 (where they were currently standing). What he was telling them (before ascending the mountain together with Yehoshua) was, that, although their place was in the camp, they were authorized to go up to that point, but no further (not even to where Yehoshua would encamp).
Ramban #2: He was instructing them to remain in the camp to represent Moshe. 3
Seforno: Before ascending to the the top of the mountain, he instructed the elders to remain where they were, outside the camp at the foot of the mountain, together with Aharon and Chur. 4
Yalkut Shim'oni: With reference to the word "Lanu", Moshe was asking the Zekeinim to Daven for himself and for Yehoshua 5 who were going to a location of Serafim, Chayos and Mal'achim
See Ramban's objection to this explanation.
As is evident from the following phrase "ve'Hinei Aharon ve'Chur Imachem ... ", implying that they were to remain in the camp (Ramban).
As implied in the word "Lanu" (Ramban). And he added " ... Yigash Aleihem" - in honor of Aharon and Chur (like we find in Beshalach, Sh'mos 17:9, when Moshe said to Yehoshua, "B'char lanu Anashim"), who would deal with any problems that the officers of thousands and hundreds ... could not handle (like Moshe himself did - See Yisro, Sh'mos 18:22 (Ramban).
Oznayim la'Torah: Because the words "Ad asher Nashuv Aleichem" imply that the Zekeinim remained at the foot of the mountain
Why did Moshe insert the word "Lanu"?
Refer to 24:14:3 & 5.
What are the implications of "Mi Ba'al Devarim Yigash aleihem"?
Bava Kama, 46b: Reading "Yigash" as if it was written 'Yagish', it implies that the claimant must present his claim to the Beis-Din (before the defendant is permitted to speak). 1
See Torah Temimah, note 31 as to how the defendant would otherwise be able to speak first. See also note 32, where he explains how the Gemara retracts from its initial D'rashah that the onus lies on the claimant to prove that the article belongs to him before extracting it from the defendant
Who was Chur?
Rashi: He was the son of Miriam and Kalev ben Yefuneh. 1
QUESTIONS ON RASHI
Rashi writes that "Efras" (Kalev's wife and the mother of Chur), was Miriam, like it says in Sotah 11b. She is called so after she was cured of her Tzara'as, after Chur was killed!
Riva: A Gaon's Perush on Divrei ha'Yamim says that the verses are not in order. It says he married the one who will be called Efras.