Bane Vs Vader preview 5 - Book Of Sith
Book of Sith, Pg 75 - The Rule Of Two - Selecting An Apprentice
"[...], the Sith Order is a lineage. It must not end with you! I will not allow my new Sith Order to expire because you were unworthy or too protective to bequeath your power.
"Know this: Your apprentice will kill you. If this fact frightens you, then the Sith Order has already suffered a fatal infection. Your existance in the Order is not needed. Your battle has already been lost."