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.
Sadducees
The Sadducees (; Hebrew: "Ṣĕdûqîm") were a sect or group of Jews that was active in Judea during the Second Temple period, starting from the second century BCE through the destruction of the Temple in 70 CE. The sect was identified by Josephus with the upper social and economic echelon of Judean society. As a whole, the sect fulfilled various political, social, and religious roles, including maintaining the Temple. The Sadducees are often compared to other contemporaneous sects, including the Pharisees and the Essenes. Their sect is believed to have become extinct some time after the destruction of Herod's Temple in Jerusalem in 70 CE, but it has been speculated that the later Karaites may have had some roots in—or connections with—Sadducaic views.