By the practice of Pranayama, ignorance is dispelled and Knowledge of the Self reveals.
When the breath is tranquil, it is the state of Kumbhaka. When one sees Oneself, it is called Brahmajnana, "the Knowledge of Brahma, the ultimate Self."
The Knowledge of Brahma, the ultimate Self, is attained by the practice of Pranayama.
If the strain is generated on the lips, throat, and teeth by the practice of Pranayama, then the knowledge is called Bhakti, or devotion.
Avidya, ignorance, is the outward state of mind; Bidya, Knowledge, is the After-effect-poise of Kriya.
Knowledge of the ultimate Self is to know Oneself by oneself.