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.
Sect of Skhariya the Jew
In the early 19th century, a number of communities appeared in Tula, Voronezh and Tambov, which followed Jewish traditions and halacha. They were also called "zhidovstvuyuschiye" and were persecuted severely in the times of Nicolas I. Since the beginning of the 20th century, they have been also called "iudeystvuyuschie", from "iudeystvo", a neutral term for the Jewish religion. Now they are generally considered a part of Jewish people (although with no real Israelite descent) and some of them have immigrated to Israel. These groups, however, are not linked to the teaching of Skhariya.