I offer thanks to You, living and eternal King,
for You have mercifully restored my soul within me;
Your faithfulness is great.
—Modeh Ani prayer recited upon awakening
I
n this week's parsha, we read about the mitzvah of challah, separating the first portion from a batch of dough, as the verse says: "Of the first of your dough you shall give a portion (challah) to G-d."
During the times of the Temple, this portion of bread was given to the priest. Nowadays, the dough is simply set aside and burnt. Nevertheless, the lessons of this mitzvah still apply today.
The word the Torah uses for "dough" is "arisa," which also means "bed." Thus, the original verse can also be translated as: "Of the first of your beds you shall give a portion to G-d."
As such, the verse can be understood as a mitzvah to give the first "portion" of our day to G-d: to acknowledge Him the moment we awake. For the manner in which we begin our day, affects the entire day. Indeed in the Modeh Ani prayer we accept G-d as the "living and eternal King." What we are saying is that G-d is in charge, and we will follow his orders all day long.
Furthermore, we are required to thank G-d for every pleasure we have, and, appreciating kindness at the very first opportunity, is basic protocol among all mankind. For this reason, the Modeh Ani, which thanks G-d for restoring life, is recited while still on our beds, immediately upon awaking—even prior to the ritual washing of the hands.
This emphasizes that nothing—not even impurity—can defile the "Modeh Ani of a Jew." Our essence, the neshama, remains intact despite any external impurities.
—from Pearls For The Shabbos Table