The above # 2442847 is from the Rabbenu Bechaya in Parshes Ki Siso. If not for the Oral Law, we would not know when is Rosh Hashanah or Shavuos. The Chasam Sofer compares this to a father who has a goldmine. He has 3 sons and wants hi son to inherit it. He teaches him the act of goldmining. He then divides it equally but since the other sons don’t know what to do with it, it automatically falls to the youngesn. The written law is the goldmine and the oral law is the act of goldmining.
