It is a fundemental belief that the Oral Torah was also given at the
revelation at Sinai. If not so, many of the things we do would be man made
or unknown. For instance, we know we cannot cook milk in meat (this in
itself would not be so simple without the Talmud) but we'd never know how
to shecht (slaughter) an animal without the Oral Law. This is just one of
many such examples.
Rabbi Mark Schaffel
Bulls Drive for Five