Reply To: Mishna Question

Torah Sebaal Peh was not allowed to be written down originally so the minimum was passed over to each recipient which sufficed then for their great understanding but as the Jews were in diaspora their minds became weaker and questions arose which they started to argue about. The Rabbenu Bachaya explains at the end of Parashas Ki Sisa that Rebbi, Rebbi Yehuda Hanasi only wrote down the minimum necessary for understanding. As the generations went on, more and more explanations and commentaries became necessary.