According to traditional Jewish law, a Jew is someone whose mother is Jewish or a person who was born non-Jewish, but converted according to Jewish law. A Jew who does not observe the commandments or Jewish traditions is still considered Jewish. The Talmud (Sanhedrin 44a) says, “A Jew, although he has transgressed, is still a Jew.”
A person who is interested in becoming Jewish needs to study the basics of Judaism before undergoing the final steps of conversion before a rabbinical court, which are immersion in a Jewish ritual bath (mikvah), acceptance and responsibility of performing the commandments, and for a male, circumcision.