Page "Judaism" Paragraph 44

Rabbinic Judaism ( which derives from the Pharisees ) has always held that the books of the Torah ( called the written law ) have always been transmitted in parallel with an oral tradition.

To justify this viewpoint, Jews point to the text of the Torah, where many words are left undefined, and many procedures mentioned without explanation or instructions ; this, they argue, means that the reader is assumed to be familiar with the details from other, i. e., oral, sources.

This parallel set of material was originally transmitted orally, and came to be known as " the oral law ".