“Never should the deepest secrets and mysteries of yoga be revealed without ascertaining the actual status of the practitioner. Only fully realized yogis know the mysteries of this most secret Divine Yoga. When a practitioner achieves adequate progress in the practice of khechari mudra, some fully realized guru in that tradition imparts to him this secret knowledge. In the absence of this secret knowledge no practitioner can cross the boundary into Divine Yoga merely on the strength of pran shakti”.