Why did Moshe say "Lechem Lisbo'a", but "Basar Le'echol"?
1.
Rashi and Seforno: The Torah is teaching us Derech Eretz - that it is in order to eat one's bread (which constitutes one's staple diet) to satisfaction, but not one's meat, which is a luxury
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(that also explains why Hashem sent the quails at night and bread in the morning - Yoma, 75a).
2
Why did Moshe add "bi'Shemo'a Hashem es Telunoseichem", which is obvious?
1.
Seforno: He was explaining that part of his Tefilah was that Hashem should send food in such a way that Yisrael should realize that their complaints were against Him (and not against Moshe and Aharon), and that He had now answered them.
3)
Why did Moshe need to say "Lo Aleinu Telunoseichem Ki al Hashem"?
1.
Sanhedrin, 110a: To teach us that if someone complains against his Rebbi,
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it is as if he complained against the Shechinah.
