Ong Namo Guru Dev Namo
Ong Namo -I bow to the subtle divine wisdom
Guru Dev Namo - I bow to the divine teacher within.
Yogi Bhajan taught this is ancient yogic mantra as a tool to relate instantly to the divine teacher within. Adi means primal or first. In Kundalini yoga, this is the first mantra that should be used for any yogic or meditative practice. It is used to tune in before Kundalini Yoga classes, to center us in the higher self, and to spiritually guide both the teacher and the students during the class.
This mantra information is from Spirit Voyage