This Shabbos, many in the Jewish world have the custom of baking a challah either in the shape of a key or with an actual key stuck into the loaf (a shlissel challah; shlissel is Yiddish for "key"). As this is the beginning of the season for planting, sowing and harvesting, we reinforce our prayers to God for material and spiritual sustenance. The key in the Shabbos challah demonstrates our desire and willingness to make our own efforts toward this goal, elevating our physical input through the sanctity of Shabbos, which nourishes the whole week; in this way, we hope to unlock the heavenly gates of sustenance.

A fresh home-baked shlissel challah, courtesy of my rebbetzin:

It is You, God, Who nourishes the largest to the smallest of creatures. No angel or minister has the ability to provide nourishment, sustenance, or support, but You, as it is written by Your servant David "The eyes of all look eagerly to You, and You give them their food in its proper time. You open Your hand and satisfy the desire of every living thing." It is also written "He gives food to all flesh, for his kindness endures forever."
The key (to sustenance) is in Your hand, in order to refine and purify people, by causing them to rely on You and to know that there is no Savior but You. - Rabbi Shlomo Alkabetz (this version appears in the sefer Reishis Chochma; a lengthier version is available in the siddur of Rabbi Shabbatai Sofer)

May we all merit be able to provide for our families and loved ones!