Chandogya Upanishad, one of the oldest Upanishad has been written during the Vedic Brahmana period. Chandogya Upanishad is associated with Sama Veda. Chandogya Upanishad is the part of Chandogya Brahman that contains ten chapters. The 7th Khanda of Chapter Eight of Chandogya Upanishad states about the Person in the Eye. Prajapati said that the Soul or the Self that is bereft of sin, free from old age, free from death, free from grief, hunger and thirst, whose desires and thoughts comes true come true, is the soul to be searched and understood. One who knows this Self achieves all his wishes and all the regions.
The devas i.e. gods and asuras i.e. demons both heard these words and thought of searching this Self through which they would be able to obtain all the worlds and all their desires. Among the gods Lord Indra and Virochana, among the demons went forth for the work. They without communicating with each other came to Prajapati with fuel in hand to gain knowledge from him. They stayed with him for thirty-two years and practised brahmacharya. Prajapati then asked him about their purpose of staying with him for so many years. They told him that they had heard him say that the soul which is free from sin, free from old age, free from death, grief, hunger, and thirst, whose desires come true and whose thoughts come true should be searched. He who is able to obtain it obtains all the worlds. Hence, they wished to obtain that Self or soul. On hearing them Prajapati told them that the person that is seen in the eye is the Self. He further explained to them that it is immortal, fearless and is the real Brahman. Lord Indra and Virochana then asked him about the one that can be perceived in the water and in a mirror. Prajapati told them that it is the same person who can be seen in eye that can be also be seen in the water as well as in the mirror. It can be perceived in everything. It is one that must be understood and realised.
