Pranayam and Meditation

Existence in the world of duality, even for an instant, is impossible without Prana, the cosmic energy, because the phenomenal universe is the differentiation of the undifferentiated Prana. Illumination does not come from merely attaining complete mastery over the sense-organs. But when mind transcends the influence of sense-impressions, the Self is realized. The enlightened mind must rule the senses. Control over the mind is attained by Pranayam and meditation. When the senses and the mind act in perfect harmony with the Self, then alone liberation is attained and the Yogi realizes himself as the absolute Self. Therefore practice Pranayam, the Kriya meditation, observing all major and minor laws in every detail. Pranayam regulates the entire system of the Yogi and enables him to attain higher realization, hence the practice of Pranayam is more desirable than living in an inharmonious state of body and mind. Besides, it is absolutely impossible to feel even the least sensory vibration without preserving in some measure the harmonious movement of Prana in the body. Pranayam must be practiced with the sole object of self-realization, otherwise it will become a veritable source of bondage. Therefore, discarding and thus being free from all phenomenal desires, practice Kriya. Since the beginning of creation, every soul has been endowed with the desire to regain its original state of absolute perfection. This desire inspires the spiritual aspirant to manifest his divinity in its fullest glory. Let him meditate on the six centers within the spine to awaken their spiritual vibrations. The spiritual vibrations of these centers, thus awakened, will keep his mind uplifted and enable it to remain established on Ajna, the spiritual eye; and finally he will be led into the Sahasraram where all consciousness of duality vanishes, and therein he will attain the supreme state of absolute, self-existent, conscious bliss.

Spiritual Interpretation of the Gita according to Kriya Yoga
Srimad-Bhagavad-Gita: The Revelation of the Supreme Self
Swami Premananda