Bar and bat mitzvah refers to the idea that the mitzvot, or commandments, of Jewish life are incumbent upon a young person at the age of 13 years. In colloquial speech, a “bar mitzvah” or “bat mitzvah” refers to the celebration in the synagogue that marks this transition to adult Jewish identity. This celebration often involves leading the prayers, reading from the Torah and Haftarah (Book of Prophets), and offering a D’var Torah, or commentary, on the portion of the week. Synagogue celebrations are often followed by a festive meal.
It is not necessary to have a “bar mitzvah” celebration in order to be considered “bar mitzvah,” that is, an adult in terms of Jewish practice. One reaches the age of majority automatically, but the celebration offers an opportunity to demonstrate one’s skills, learning and commitment.