Seeing as there is no food in Heaven, nor did Moshe take food with him when he ascended the mountain, why does the Torah need to inform us that he did not eat for forty days?
Oznayim la'Torah: The Torah is telling us that not only did Moshe not eat whilst he was on Har Sinai, but that he did not even eat before ascending, for the meal to last forty days. 1 In fact, he even waited seven days before ascending, in order to cleanse him from all food and drink in his stomach. 2
Oznayim la'Torah: Like we find by Eliyahu ha'Navi before he entered the cave - See Melachim 1, 19:8.
See Yoma, 4b.
Bearing in mind that Moshe was human, why did he not eat during the forty days that he was on Har Sinai?
Bava Metzi'a, 86b: Because he found himself among the angels who do not eat - to teach us that one should always adhere to the Minhag ha'Makom. 1
When you're in Rome do as the Romans do'. Bava Metzi'a, Ibid.: And it is by the same token that when the angels came down to visit Avraham, they ate the food that he prepared for them.
How did Moshe survive for forty days without eating?
Oznayim la'Torah: He was fed by the splendor of the Shechinah.
The current Pasuk implies that Moshe wrote on the second Luchos, like Hashem commanded him (in Pasuk 27). But in 34:1, Hashem said that He would write them, as implied in Eikev Devarim, 10:2-4?
Ramban, Rashbam and Moshav Zekenim (in Pasuk 30): The Pasuk means that Hashem wrote them 1 , as He said He would, and Pasuk 27 refers to other issues. Refer to 34:27:1:2 & 4.
Moshav Zekenim (in Pasuk 1, citing R. Yeshayah): In fact, Moshe wrote them, and in the Pasuk earlier, Hashem meant that He would instruct 2 Moshe to write them. 3
Seforno: Refer to 34:27:1:3.
See also Rashi in Pasuk 1, citing a parable which implies that Hashem wrote them (PF).
Moshav Zekenim (in Devarim 10:4): The entire Parshah here indicates that Hashem wrote them, whereas in Ki Sisa, it implies that Moshe wrote them! This requires investigation. (Also the Seforno states here that Moshe wrote them, but he does not ask from Devarim. Perhaps Moshe wrote with a chisel, but he did not exert enough force to carve out the letters - and because it was a miracle, the writing is attributed to Hashem - PF).
Moshav Zekenim: The Midrash supports this. When it states that had the first Luchos not been broken, the angel of death and the nations of the world would not have had jurisdiction over Yisrael. Now had Hashem written also the second Luchos, in what way were the first Luchos superior? (Perhaps because they were also carved by Hashem)?
