The laws aren't the literal word of God though, because a lot of them come from the rabbis. The problem is that we don't have the rabbinic authority to overturn laws that don't apply anymore, so we're stuck with what we have a little bit.
As a former LDS/Mormon (now effectively humanist/atheist), this concept of authority is pretty interesting. One of our core lessons when I was a missionary was that God's authority was lost from the Earth, and had to be restored by a new line of prophets. Some of my fellow missionaries enjoyed discussing this with messianic Jews in the area, sharing interpretations back and forth.
So in Judaism, are there tiers of rulemaking authority? Could a rabbi override a previous rabbi, but not a prophet?
The important bit is that an individual rabbi cannot overturn anything; the power comes from a legislative entity called "The Sanhedrin". However, in order to be part of the sanhedrin you need to be ordained by another member of the sanhedrin and at some point (unknown exactly when, possibly around the year 400) this lineage was lost. The idea of overturning a prophet doesn't really matter though, because as far as I know we don't get laws from the prophets (except Moses obviously).
