“The illuminating, joyous vibration of the ascending current of Pranic force resembles the tone quality of the hum of the bumblebee at Muladhar, coccygeal; that of the melodious note from a violin at Sadhisthan, sacral; that of the sweet call of a flute at Manipur, lumbar; that of the deep and vibrant roar of a conch at Anahata, dorsal; that of the reverberation of rolling thunder at Visuddha, cervical; and that of a universal symphony of exalting blissfulness at Ajna, the spiritual eye. Besides these there are also felt in this body temple the power of calmness of mind and poise of the senses, clear conscience and love of truth, intuition and enlightened perception, as well as the power of purified consciousness and self-realization. The illuminating power and joyousness of these vibrations are beyond the conception of mind. This cosmic vibration, resounding throughout the entire being and consciousness, spiritualizes the faculties of the senses, transforms the will of the sense-attached mind, and liberates the self from sense-identification.” (1:15-19)
“When the mind is absorbed by the cosmic vibration, AUM, then the power of understanding becomes pure, the mind remains established on the Self at the spiritual eye, and finally the Self is revealed.” (2:53)
“The practice of Kriya spiritualizes the perceptive and cognitive faculties by raising the sensitivity of the entire nervous system to a highly perfected rate of subtle vibration; and in this state the self is realized in the body and finally the absolute Self is revealed as the transcendental, illimitable consciousness.” (8:3)
—Swami Premananda, A Spiritual Interpretation of the Srimad-Bhagavad-Gita: The Revelation of the Supreme Self