When is "ba'Eis ha'Hi" referring to?
Ramban: It refers to when Yisrael were staying in Chorev, and it refers to the advice of Yisro - before Hashem said to them "Rav lachem Sheves ba'Har ha'Zeh (Pasuk 6). 1
Oznayim la'Torah: it refers to the period preceding the conquest of Cana'an - which Hashem intended to follow immediately - because on the merit of appointing Kasher judges, they would defeat their enemoies and settle the land. 2
According to the opinion that Yisro came before Matan Torah, which was long before they left Harr Chorev, why does the Torah write "ba'Eis ha'Hi"?
Oznayim la'Torah: Because, even though Yisro presented the plan to appoint judges as soon as he arrived, Moshe did not appoint them until Hashem taught him the Mishpatim, since, without a framework from which to draw, the judges would then have had to judge according to their own viewpoint - something that Moshe wanted to avoid.
Why did Moshe insert the (otherwise superfluous) word "Leimor" (See Sifsei Chachamim)?
Rashi: To inform them that what he was about to say was not his personal statement 1 but was dictated by Hashem.
Targum Yonasan: He actually informed them that he would not leave them to be judged by a single judge, 2 but would appoint judges.
How is it possible that Moshe, who took them out of Egypt, split the Sea for them, brought down the Manna and blew in the quails, was unable to judge them?
Rashi: It was not a question of able or unable, but rather one of responsibility - since Hashem placed the people above their judges 1 by taking away the punishment for Yisrael's sins from them and placing it on their judges 2 (their leaders). 3
Rashi: As stated in the following Pasuk.
See Sifsei Chachamim.
Rashi: And Shlomoh ha'Melech made a similar statement, when he said in Melachim 1, 3:9 "Ki Mi Yuchal Lishpot es Amcha ha'Kaved ha'Zeh" - with reference to Jewish judges, who, as opposed to Nochri judges who are not taken to task for sentencing a defendant to death unjustly or for perverting justice and robbing (See Rashi). If a Jewish judge unjustly extracts money from a litigant, it is considered as if he took his life.
Why did Moshe insert this Pasuk here?
Ramban: He was pointing out that, having received the Torah and appointed judges and policemen to judge them, they were ready to enter Eretz Yisrael. They had indeed traveled from Chorev, the tribes in the order of their flags with their judges and their elders, but when they approached him together with their sages and elders with the request to send spies, everything fell apart.
QUESTIONS ON RASHI
Rashi writes that also Shlomoh said "Mi Yuchal Lishpot?" That was before Hashem made him 'Chacham mi'Kol Adam'; he asked for Chochmah! How can we learn from him to Moshe?
Moshav Zekenim and Riva (citing R. Tam of Orleans): Because, since Hashem gave Shlomoh extra Chochmah, presumably, he was already a Chacham. 1
Moshav Zekenim and Riva: As the Pesukim write in Mishlei 9:9, Daniel 2:21, Sh'mos 31:6, respectively "Ten le'Chacham ve'Yechkam Od.", "Yahev Chachmesa le'Chachamin u'Mand'a le'Yod'ei Vinah", "u've'Lev Kol Chacham Lev Nasati Chochmah".
