Which system guides Jewish society and behaviors, including how people pray and celebrate holidays?

The system that guides Jewish society and behaviors, including how people pray and celebrate holidays, is Judaism, which encompasses the religion, philosophy, culture, and way of life of the Jewish people. Central to Judaism is the Torah, which is the foundational text for Jewish laws and ethics. These laws and ethical guidelines are known as "halacha". Halacha covers every aspect of life, including prayer, diet (such as keeping kosher), holidays, and every day interactions and behaviors.

Jewish holidays such as Passover, Rosh Hashanah, Yom Kippur, Sukkot, Hanukkah, and others are governed by specific halachic instructions. For instance, on Passover, Jews are commanded to refrain from eating leavened bread and to hold a Seder meal that retells the story of the Exodus from Egypt. The way Jews pray is also dictated by halacha; there are prescribed prayers for different times of day, which are compiled in a prayer book known as a Siddur.