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 religious movements
The very idea of Jewish denominationalism is contested by some Jews and Jewish non-denominational organizations, which consider themselves to be "trans-denominational" or "post-denominational". A variety of new Jewish organizations are emerging that lack such affiliations:Organizations such as these believe that the formal divisions that have arisen among the "denominations" in contemporary Jewish history are unnecessarily divisive, as well as religiously and intellectually simplistic. According to Rachel Rosenthal, "the post-denominational Jew refuses to be labeled or categorized in a religion that thrives on stereotypes. He has seen what the institutional branches of Judaism have to offer and believes that a better Judaism can be created." Such Jews might, out of necessity, affiliate with a synagogue associated with a particular movement, but their own personal Jewish ideology is often shaped by a variety of influences from more than one denomination.