What sort of preparations was Hashem referring to?
Rashbam: To bake or to cook, as they saw fit. 1
Seforno: To prepare on Erev Shabbos nice foods to enjoy on Shabbos.
Targum Yonasan: He was referring a. to preparing the food that it should be ready to eat (to avoid the Isur of Muktzah), 2 and b. the various types of Eiruv that they needed to arrange on Eirev Shabbos to enable them to carry from one house and from one Chazter to another. 3
Beitzah, 2b: It refers to a verbal preparation 4 - and it implies that, whereas one needs to prepare for Yom-Tov and for Shabbos on a weekday, Yom-Tov cannot prepare for Shabbos or vice-versa. 5
Shabbos, 117b: It refers to rising early on Erev in order to prepare for Shabbos. 6
In accordance with the instructions in Pasuk 28.
See Na'ar Yonasan.
Even though all of this is only Asur mi'de'Rabbanan. See Na'ar Yonasan.
See Torah Temimah, note 8.
Consequently, an egg that was completed inside the chicken on Yom-Tov thaqt falls on Friday is Muktzah on Shabbos, and similarly, an egg that is completed on Shabbos that falls on Erev Yom-tov is Asur on Yom-Tov. Some commentaries explain that it is because of Muktzah, and they bring a poof from here that Muktzah is d'Oraysa. See Torah Temimah, citing Pesachim, 47b and note 10.
See Torah Temimah, note 9.
What are the ramifications of the statement "Vehayah Mishneh ... "?
Rashi: When the people arrived home on Friday with the Manna that they had collected, they discovered that the Omer that they had collected had doubled and had become two Omrim.
Rashbam: When they went to collect the Manna from outside the Camp, they discovered two Omrim for each person in the family, instead of just one, like on every other day.
Seforno: Even after they cooked the Manna, what they cooked for Shabbos had not diminished (as usually happens when one cooks food), but the full amount was still intact.
Ba'al ha'Turim: Everthing connected with Shabbos is douable - two lambs (the Korban Musaf), two loaves (the Manna), two lamps (Ner Shabbos), 'Zachor' and 'Shamor' (on the two sets of Luchos).
