AJNA CHAKRA or the brow center is the location of the third eye or the divine eye. In the upper part of the brain, the well-known sahasrara chakra or the thousand-petaled lotus exists. This is also known as Brahma Randhra or the niche of Brahman. It is in this thousand-petaled lotus the subtle body of man exists. The subtle body or "sukshma sharira" consists of the mental and intellectual sheaths. In other words, that is the location of the mind and its discriminating faculty known as the intellect. Through the senses of perception or cognition, the mind and the intellect accumulate worldly knowledge when they are extroverted.
When the mind and the intellect are introverted during deep meditation, if the light of the Self pierces through the chitta or subconscious, then the mental and intellectual sheaths are illumined. If the thought of knowing anything super-sensuous from anywhere in the universe is held, then this light of the Self pierces through the ajna chakra. This is known as opening of the third eye. The shining rays of this light of the third eye are capable of knowing things of the past, present and the future. Extrasensory perception, clairvoyance, etc., are the mind powers which a man acquires by the glimpse of this light. Knowledge of the past, present and future of individuals and of the world comes to a yogi by the opening of the third eye. All knowledge is at hand to such a Master. Just as there are different functions to different parts of the body, similarly, the ajna chakra, or the brow center, is the channel through which the Self expresses its light. The light that emerges from the third eye blesses the deserving ones and destroys the darkness.
It is said that once Lord Shiva was in deep meditation. Celestials sent Manmatha or Cupid to tempt him. Cupid tried to enchant the mind of Shiva by discharging his flowery arrows. Shiva's mind was disturbed in meditation. Then he opened his third eye. The fire that emerged out of his third eye reduced Cupid to ashes. Then Shiva smeared the ashes all over his body. This is a symbolic story of the destruction of lust, or Cupid, by the opening of the third eye. In other words, the opening of the third eye brings a man the light of wisdom.
HOW TO OPEN THE THIRD EYE
Develop sattvic or tranquil qualities by a yogic diet, study of the holy scriptures, chanting, worship of the Lord, keeping the company of saints, fasting at times, maintaining silence for a few hours every day, etc. Once your mind becomes pure you can go into deep meditation and invoke the power of the Self through a noble decision, and the light of the Self reflecting through the transparent mind and the intellect pierces through the ajna chakra or the brow center. Then the third eye opens itself and brings the seeker unlimited knowledge.
WHERE IS THE LOCATION OF THE SOUL AND SELF IN THE HUMAN BODY?
You have read that there are five "koshas" or sheaths in the human body. They are known as "annamaya kosha" or the food sheath, "pranamaya kosha" or the vital sheath, "vijnanamaya kosha" or the intellect sheath, and "anandamaya kosha" or the bliss sheath. It is this last sheath, anandamaya kosha or the bliss sheath, where the soul and God, or the Self, are located in the human body. All of us know that God is everywhere, but He is realized in our own soul. Because the soul is the most transparent of all that exists, being the spirit, you realize God within the soul as the Soul of all the souls. Soul has its center in the anandamaya kosha and God is within all the souls. Therefore, men of wisdom teach that the Self is to be meditated upon in the heart, where the soul is located. It is this sacred heart or "hrit padma that is known as anandamaya kosha or the bliss sheath. Just like the ethereal space of akasha outside, the space inside the heart is known as "hridaya-akasha"or the heart's ethereal space. Brahman or the Self is fully manifesting in this heart's space, shining like thousands of suns.
The well-known Gayatri mantra glorifies this Self and prays for the illumination of the intellect. We are asked to meditate in this heart's lotus on Brahman or the Self. Even as the fire pervades inside and outside of a hot iron rod, similarly, the Self pervades the soul inside and outside of it. The yogi realizes the Self first in the soul and then he is able to see it everywhere.
(Essence of Bhagavad Gita and Bible, p. 82.)