Vibrations are the pulsation of the all-pervading power within us, which we can feel in the central nervous system. The Spirit doesn't pulsate. It doesn't pulsate. The pulsation exists in the all-pervading power. But through Spirit when you get connected, then only the flow starts. And you then start feeling the pulsation on the central nervous system. And these pulsations of the Holy Ghost are the vibrations.
H.H.Shri Mataji Nirmala Devi, Delhi, 8/2/83
(Nirmala Yoga no.29, p35)