The Garuda Purana
Chapter CCXLVII - Synopsis of the Gita
The God said:— O thou, who art conversant with all the Vedantas, who hast practised Yoga with all its eight essential components, now hear me discourse on the synopsis of the Gita as formerly narrated to Arjuna. Realisation of self is the Summum bonum of human life; this self is devoid of body, form, egoism, mind and the senses such as, the eyes, etc. Bereft of sensations, this receptacle of life (self) appears to be in a state of dreamless sleep. I am Self, not the combination of misery and phenomena. The self, effulgent as a smokeless fire, like a flash of lightning in the sky, burns itself in the cavity of the heart. The senses such as, the ears etc., do not perceive, it is the omniscient, all-seeing, self-conscious, individualised self (Kshetrajna), that perceives through the means of senses.
When through the extinction of sin, the self is reflected on the mind, like a burning flame on a screen, the right knowledge is originated. Like images of objects reflected in a mirror, the self witnesses the objects of sense-perception, the five kinds of gross matter, the mind, the intellect, and the sense of Egoism reflected in itself. When an individualised self sees itself as universal and running through all, it becomes emancipated.
O thou son of Pandu, by merging all the senses in the mind; the mind, in the sense of Egoism; the sense of Egoism, in the principle of intellection; the principle of intellection, in the Prakriti (Nature); the Nature, in the Purusha (self); and the Purusha, in the Atman (supreme Self) that a man becomes emancipated and perceives his oneness with Brahma, the supreme light. The intelligent one, who rightly understands the nature of his organism, provided with nine apertures (external ducts of the body), three supports (the fundamental principles of Vayu, Pittam and Kaphah), five witnesses (the cognitive organs) and lorded over by the self-conscious Ego, is the true seer (Kavi).