1)
Why does the Torah mentions specifically overnight, a day and a night, two days a month and a year?
1.
Ramban #1 and Seforno: Refer to 9:17:2:1.
2.
Ramban #2: It may well be that the Torah mentions them because those were the actual time-periods - exclusively - that Yisrael encamped in the desert. 1
3.
R. Bachye: The Torah writes 'a day and a night' - and not the other way round, 2 to teach us Hashem's kindness with Yisrael, inasmuch as He never troubled them to break camp by night; they always began traveling in the day.
