The passuk says ותעל שכבת הטל, “and the tal, dew, went up, evaporated.” This teaches that the tal was on top of the mon. However in Parshas Beha’aloscha the passuk says וברדת הטל, the tal descended and the mon was upon it. The Gemara brings Rebi Yosi B’Rebi Chanina explained that there was tal on top and tal on bottom with the mon inside as in a container. The Maharsha adds since they asked properly for mon it was given in a pleasant way.
The Rama brings some places have a custom to eat pashtida on Shabbos night. Pashtida is dough filled with meat or potatoes. There is another custom which Tosefos brings, that we cover the challos on top and bottom. These are both a remembrance of the mon which was covered on top and on bottom. The Tosefes Shabbos explains that since the mon did not fall on Shabbos there’s a point to remember it.
The Biur Halacha asks, since the mon didn’t come down on Shabbos why is there a need to remember it on Shabbos? Also, why isn’t there a custom to eat pashtida on Yom Tov, since there are opinions that the mon didn’t come down on Yom Tov as well?
The Tosefes Shabbos brings from the Toras Chaim that the seuda we have on Shabbos is in anticipation for the seuda that will be l’asid lavo. Hashem will make a seudah for the tzaddikim consisting of wine which was put in safekeeping, fish of the livyason, meat of the shor habor and mon. This is why on Shabbos it is customary to drink wine, eat fish, meat and pashtida. The pashtida and covering the challos on top and bottom are specifically done as a reminder of the mon that will be served by the special seuda l’asid lavo.
May Hashem bring the geulah soon and we should all be zoche to eat the special seudah l’asid lavo!