"In the Mahayana which develops the inner qualities of compassion and wisdom, a teacher is more important. Involving more aspects of our totality, it helps to have a living example and somebody to watch our development. But the Diamond Way does not even start without a teacher. If no one carried the living experience and was able to pass it on, intellectual or cryptic books and pictures whose aesthetics one might like or not like would be all that we have. If there were no living holder of the experience, there would be no access to their transformative power.
So, for the highest level one needs a teacher. It is important, however, to see him or her not as a person or god but as a mirror to one's own potential. Showing us our timeless nature with countless skillful means, he actually represents the Buddha"
Lama Ole Nydahl
Karmapa International Buddhist Institute, New Delhi, India, 1994