Satan
Each sect of Judaism has its own interpretation of Satan's identity. Conservative Judaism generally rejects the Talmudic interpretation of Satan as a metaphor for the "yetzer hara", and regard him as a literal agent of God. Orthodox Judaism, on the other hand, outwardly embraces Talmudic teachings on Satan, and involves Satan in religious life far more inclusively than other sects. Satan is mentioned explicitly in some daily prayers, including during Shacharit and certain post-meal benedictions, as described in Talmud and the Jewish Code of Law. In Reform Judaism, Satan is generally seen in his Talmudic role as a metaphor for the "yetzer hara" and the symbolic representation of innate human qualities such as selfishness.
Historical background of the New Testament
Historians seek to understand where Jesus and his followers fit among other Jewish factions at the time. According to the Jewish-Roman historian Flavius Josephus, the three parties in contemporary Judaism were the Pharisees, the Sadducees and the Essenes, the last of these three being apparently marginalized and in some cases retired to quasi-monastic communities. Josephus also speaks of a "Fourth Movement", "Zealots", "Lestai" or "Sicarii".
The Pharisees were a powerful force in 1st-century Judea. Early Christians shared several beliefs of the Pharisees, such as resurrection, retribution in the next world, angels, human freedom, and Divine Providence. After the fall of the Temple, the Pharisaic outlook was established in Rabbinic Judaism. Some scholars speculate that Jesus was himself a Pharisee. In Jesus' day, the two main schools of thought among the Pharisees were the House of Hillel, which had been founded by the eminent Tanna, Hillel the Elder, and the House of Shammai. Jesus' assertion of hypocrisy may have been directed against the stricter members of the House of Shammai, although he agreed with their teachings on divorce. Jesus also commented on the House of Hillel's teachings (Babylonian Talmud, Shabbat 31a) concerning the greatest commandment and the Golden Rule. Historians do not know whether there were Pharisees in Galilee during Jesus' life, or what they would have been like.