"the scrolls also contend that God has already chosen the sons of light and the sons of darkness. "
In advocating that initiates withdraw from the "sons of darkness," the rule texts imply that members broke ties with others in their usual company, such as their families. This is a striking and yet familiar pattern in sectarian development, as the sect establishes tight boundaries around itself that preclude the previous networks in which members traveled.
The first couple sentences are interesting. The pattern is seen amoung many cults, including the Mormons.
Although it appears that the core of the Jewish law, the Torah, was fairly well established at Qumran in its written form (Genesis-Deuteronomy), that does not mean that the law was static or rigid. This apocalyptic community gave its instructors great latitude to interpret that law in a manner that was at once faithful to it and at the same time very creative with it
It looks like there were a bunch of liberals at Qumram. The Law was not rigid, but in fact static and allowed creative interpretations.
The rules and halakhic material found in the Qumran caves stipulate ethical behavior that represents a rather strict interpretation of the Jewish law. Much emphasis was placed on observing the law and being judged for how well you did that.
Calvin may not have been a Qumram dude. It looks like there was some emphesis on works leading to some salvation.