and the Interpretations can change, or be contradictory?
how is that from God?
It's not from God. Apparently, Rabbis have the authority to modify the Laws given by God.
One example is how the prohibition on cooking animals with their mothers milk was modified into a prohibition on eating chicken and cheese sandwiches.
Another example is the Law concerning the Sabbath. In the Torah, gentiles living in Israel had to keep the Sabbath.
“Remember the Sabbath day by keeping it holy. 9 Six days you shall labor and do all your work, 10 but the seventh day is a sabbath to the LORD your God. On it you shall not do any work, neither you, nor your son or daughter, nor your male or female servant, nor your animals, nor any foreigner residing in your towns. (Exodus 20:8-10)
But the Rabbis "interpreted" the Torah to mean they can hire gentiles (i.e., foreigners) to do work that couldn't be done by Jews.
Another example of Rabbis modifying Sabbath Law would be the strings that certain Orthodox Jewish communities tie around their neighborhoods. You see, they have a rule that on Sabbath it's impermissible to carry an object from the inside of the house to the house. But if the string is tied around the neighborhood, the outside is counted as part of the "inside" of the house!!!!! And thus, people are allowed to carry objects in and out of the house without breaking the Sabbath! LOL.