The mandala of guru and disciples is particularly important in vajrayana. The patterns of relationship, as they occur in everyday life, are unpredictable and disordered. Sometimes they work and sometimes they do not, but in general we do not have much control over them or much awareness of what is really happening within them. The mandala of the deities, on the other hand, arises from a state of natural perfection and harmony, reflected in the formal arrangement of mandala painting and structures.

The Mandala Of Guru And Of Deities
Csaba Osvath

Notes from
Francesca Fremantle: Luminous Emptiness; Understanding The Tibetan Book Of The Dead.
(page 115-116)