Jewish boys and girls under the ages of 13 and 12 respectively are not required to observe the commandments other than for the purpose of education. However, upon turning 13, a boy is considered an adult according to Jewish law and is expected to obey all the commandments from then on. He has become a Bar Mitzvah, or son of the commandments. Similarly, a girl becomes a Bat Mitzvah, daughter of the commandment, upon turning 12.
A Jewish youth automatically becomes Bar or Bat Mitzvah upon reaching the appropriate age. The accompanying ceremonies are not necessary to attain this status, and they are not mentioned in the Torah or Talmud. Many parents choose to make a celebratory ceremony for a Bar and Bat Mitzvah in order to impress upon their children the importance of this milestone in their Jewish lives.
In its earliest observance, the rite of passage was marked by a boys first reciting of the aliyah (call up to the Torah reading) at the first Shabbat service after his 13th birthday, after which the father says a blessing, thanking God for removing from him the burden of responsibility for his childs sins. These duties have gradually increased over the years, and may now include reciting the haftarah (selection from the Prophets), reading the weekly Torah portion or leading part of the prayer service. It is also customary for the youth to make a short speech, which should contain a message from their Torah portion.
Spiritually, the ages of Bar and Bat Mitzvah are of much significance. According to the Kabbala (or Jewish mysticism) a Jewish person actually possesses two souls. The first is of an animalistic nature. The second is of a G-dly nature. Although the animalistic soul of a Jewish child is invested in their bodies at birth, their G-dly soul is only introduced to the body at this time but is not fully attached. There is a gradual process throughout their childhood during which the G-dly soul becomes more and more attached to their bodies. This process culminates at the age of Bat or Bar Mitzvah when this higher soul fully permeates the childs body and equips them with a stronger sense of purpose and spiritual identity. Hence, it is at this time when he or she becomes obligated in the commandments of the Torah.ls
for more details See Bar Mitzvah Program details