Judaism
Christianity was originally a sect of Second Temple Judaism, but the two religions diverged in the first century. The differences between Christianity and Judaism originally centered on whether Jesus was the Jewish Messiah but eventually became irreconcilable. Major differences between the two faiths include the nature of the Messiah, of atonement and sin, the status of God's commandments to Israel, and perhaps most significantly of the nature of God himself. Due to these differences, Judaism traditionally regards Christianity as Shituf or worship of the God of Israel which is not monotheistic. Christianity has traditionally regarded Judaism as obsolete with the invention of Christianity and Jews as a people replaced by the Church, though a Christian belief in dual-covenant theology emerged as a phenomenon following Christian reflection on how their theology influenced the Nazi Holocaust.
Jewish education
The Conservative movement has USY - United Synagogue Youth. The Modern Orthodox movement has NCSY - formerly National Conference of Synagogue Youth. BBYO is a non-denominational group, though most Jews associate it with the Conservative or Reform movements. The North American Federation of Temple Youth, known as NFTY, is the organized youth movement of Reform Judaism in North America. Funded and supported by the Union for Reform Judaism, NFTY exists to supplement and support Reform youth groups at the synagogue level. About 750 local youth groups affiliate themselves with the organization, comprising over 8,500 youth members.