svapnamantrālabha nyāyaḥ (obtaining mantra in a dream)
One dreams that he has gotten a mantra.
First of all, I would like to explain that sound vibration is the most powerful element in the material world, which has its origin beyond. All religions admit that fact. Even in material dealings, we can observe that by sound individuals and masses can and are manipulated for good or bad purposes.
The same principle applies in the spiritual dealings of Krishna consciousness. As any disciple is getting information through the voice of his teacher, so is true for the aspirant devotee of the Lord. Eternally had all the gurus imparted mantras to their disciples, thus allowing them to do the same. Any common man can understand this. Yet there are men of devious character who break this line and proclaim that there are no more qualified persons who can impart mantras to others, yet at the same time, they impart mantras on their own authorization. What a cheating! Thus both parties live a dream of falsity and an imagined spiritual process. Krishna confirms the proper method in Bhagavad-gita where He states that the disciple has to surrender to his teacher, serve him and inquire from him.