The primary function of the Lama

It is the Lama who gives us access to countless powerful methods of realisation.   
Lamas are teachers in a larger sense.  Lamas are not conditioned in any way by the style they adopt.  They may utilise many different styles according to the personality, capacity, and circumstances of those whom they teach.  Whatever method is implemented by the Lama, it transcends the function of the method as it is usually employed.  The Lama is in a completely different category.  So if we are to approach such a person; we need, at least, to be open to the unexpected.  We need to be prepared to question our range of perceptions and responses.  We need to be open to having our rationale actively challenged.
The Lama’s function is to mirror our intrinsic enlightenment.  The Lama shows us the nature of what we actually are.     

p145, Wearing the Body of Visions, Ngakpa Chögyam, Aro Books, 1995, ISBN 1-898185-03-4

Cutting through the mountain of our mental distortions and neurotic mind-states.

Practising meditation on your own with only yourself as a guide could be compared to wearing away a rock with water from a gentle stream – the water will erode the rock, but it will take a long time to have any great effect and the effect may lack focus.  Becoming part of a spiritual tradition and working with a teacher is like turning our gentle stream of spiritual practice into a powerful, focused, torrent that will quickly cut through the mountain of our mental distortions and neurotic mind-states.

p151,  Relaxing into Meditation   Ngakma Nor'dzin,  Aro Books Worldwide, 2010, ISBN 978-1-898185-17-8 

Relationship with the teacher in Vajrayana

  The relationship between teacher and student is fundamental to Vajrayana.  Within the theatre of this relationship you can become transparent to yourself, and through becoming transparent, your constricted sense of being is liberated.
Devotion to the Lama enables the student to be empty in relation to the Lama.  This allows the Lama to conjure with the form of the student’s neuroses to mirror them, so that they become transparent for the student.
If one is open to receiving transmission, then a great deal can be achieved in such moments.  Huge shifts can be made in an instant.  This is only possible within a relationship based on confidence in the teacher and openness in the student.

p59 and 62, Illusory Advice Ngakma Nor’dzin and Ngakpa ’ö-Dzin, Aro Books, 2015, ISBN: 978-1898185-37-6 

Transmission

"... transmission means sharing the experience of the nature of the teacher’s mind: nothing actually moves."

Buddhism in the West, Ngala Rig’dzin Dorje, Aro Encyclopaedia

Coming to trust your own enlightened nature

"Lama’i Naljor is really a way of coming to trust your own Enlightened nature. Lama’i Naljor authenticates the relationship between Teacher and student and it also enables you to authenticate the sense in which your Enlightened nature can be momentarily experienced. "

Lama'i Naljor, Ngak’chang Rinpoche, Aro Encyclopaedia