Shabbos and Mahn

שמות טז ,כה : א כְלֻּהוּ הַיוֹם כּ י־שַבָת הַיוֹם לַה' הַיוֹם לֹא ת מְצָאֻּהוּ בַשָדֶה

The Sforno notes that the word הַיוֹם (today) appears three times in this Pasuk to teach us three things:

1. Although the entire amount of Mahn was in one’s hands from the eve of Shabbos it should not be consumed at once but appropriated for specific meals.
2. Although the food prepared of the eve of Shabbos can be used the entire day of Shabbos but not the next day.
3. This order is to be followed every week on the Shabbos.