Sadducees, Pharisees and Hellenists
One of the essays in the back makes an interesting point. The position of the Sadducees, coming from a priestly position, was that holiness was a function of birth - this makes sense as their priestly status and hence importance was inherited. The Pharisees and later the rabbis held that holiness was something that can be achieved by anyone through proper education and behavior, regardless of your birth. This is strikingly similar to the position of Hellenists in the Greek world - regardless of your birthplace or background, you could be educated and "transformed" into being "Greek".