What is the meaning of the phrase "א-להי הרוחות לכל בשר"- "The G-d of the spirits of all flesh"? [See Rashi, Ohr Hachaim and many more commentaries].
In פסוק י"ז Rashi writes:
אשר יצא לפניהם: לא כדרך מלכי האומות שיושבים בבתיהם ומשלחין את חיילותיהם למלחמה, אלא כמו שעשיתי אני שנלחמתי בסיחון ועוג, שנאמר (במדבר כא, לד) אל תירא אותו. וכדרך שעשה יהושע, שנאמר (יהושע ה, יג) וילך יהושע אליו ויאמר לו הלנו אתה וגו'. וכן בדוד הוא אומר (ש"א יח, טז) כי הוא יוצא ובא לפניהם, יוצא בראש ונכנס בראש:
who will go forth before them: Not like the kings of the [gentile] nations, who sit at home and send their armies to war, but as I did, for I fought against Sihon and Og, as it says, “Do not fear him” (21:34), and as Joshua did, as it says, “Joshua went to him and said to him, Are you for us [or for our enemies]?” (Josh. 5:13). Similarly, concerning David it says, “For he went forth and came in before them” (I Sam. 18:16) -he went out [to battle] at their head and came in before them. — [Sifrei Pinchas 23]
That explains the words "אשר יצא לפניהם" but how do we understand "ואשר יבא לפניהם"? What is the significance of Moshe coming before his soldiers?
On the words "ואשר יוציאם ואשר יביאם" - "who will lead them out and bring them in", Rashi says "with his merits" [בזכויותיו]. The Sifrei says that the request was that he should lead them out and bring them in with the same number of soldiers, meaning that none should be lost in war. So the idea of his merits is just an explanation of how they will not lose any soldiers. So why does Rashi not mention the basic request of not losing any soldiers and only mentions the merits? Where do we see merits mentioned in the pasuk?
Moshe says "ולא יהיה עדת ישראל כצאן אשר אין להם רעה" - "so that the congregation of Hashem will not be like sheep without a shepherd". The Ohr Hachaim asks that this is simple and self understood. Would Hashem leave the Jews leaderless??!
Also, why do we find that only MOSHE made a request for a successor when we don't find this regarding other Jewish leaders and kings in Biblical history?