I heard this distinction somewhere, and being a Judaism dummy, wasn’t sure what to make of it. (and this distinction, in turn, lead to anti-semitic persecution throughout the centuries). If someone could break it down for me like I’m a ten-year old, that’d be great.
The Judaism of Jesus’ days consisted of approximately 24 different varieties. The best known today are the Judaism of the Pharisees and the Judaism of the Sadducees. Rabbinical Judaism is largely in the tradition of the Pharisees, but not exclusively so. There are minor differences, such as the absence of Temple offerings and rabbis replacing High Priests, but the major beliefs and practices are not so different as some would believe. Judaism is still founded on the Written Law (Torah/Pentateuch) and the Oral Law transcribed in the Mishnah of the Talmud and further commented upon by rabbis in the Gemara of the Talmud. The mystical Kabbala, particularly the Zohar, is also used by some in the Orthodox Jewish community for further enlightenment regarding the meaning of the Torah, but the latter remains the supreme Law in Judaism, together with the Talmud, according to Orthodox Jews.
Various Jewish sects aside, probably the shortest answer is that Judaism faced a huge transition shortly after Jesus’ time with the destruction of the Jewish temple in Jerusalem. Judaism of Jesus’ time centered on the temple and its tradition of offerings. The temple also contained to holy of holys which in the temple of David contained the ark. In the time of Jesus and the second temple the ark was lost, but it remained the center of Jewish life. The Rabbinical Judaism we have today developed out the loss of the second temple as an answer to the problem of no longer having a temple since the Jews were never able to rebuild the temple a third time.
It might be suggested in signifficant aspects that portions of Judaism today are a reaction to Christianity. Certaintly Judaism at the time of Christ was much more varied with differing opinions by obscure or prominent sects. At least this is how I know.