We purchase challah bread so that we can say HaMotzi, the blessing over bread before a Shabbat meal. We also say kiddush, which is a blessing recited over grape juice or wine to sanctify Shabbat. There are a variety of other prayers and blessings that can be added to the Shabbat meal, but HaMotzi and kiddush are the most common.
In the Torah, or Jewish Bible, God created the earth in six days and rested on the seventh. The purpose of Shabbat is to honor the seventh day and to take a break from the rest of life. It is also a time to reflect on the work of God and the hard work that is being done by everyone. The day encourages refraining from labor and other forms of work, and celebrating spending time with family, singing and eating. Though inconvenient for visitors to Israel that do not practice Shabbat, the day of rest is something I really appreciate. Though I do not identify with the Jewish faith, I find it gives me the opportunity to reflect on my school week and appreciate all that I have accomplished and what needs to be done when the week begins again.