To understand this excerpt, it is important to know that in Hindu tradition people focus on God, the Ultimate Reality, by outwardly and inwardly reciting the word A-U-M (OM).
The God who is both higher and lower,
who is called by the name of OM,
is soundless and devoid of being.
Therefore a person should concentrate on the highest place.
The body is the bow,
the syllable OM is the arrow,
the mind is its tip,
darkness is the goal.
Piercing darkness one reaches that which is not wrapped in darkness.
Piercing that which is wrapped in darkness one beholds God.
One sees as it were a sparkling wheel of fire, of the color of the sun, powerful, beyond darkness, the Ultimate that shines in yonder sun, in the moon, in fire, and in lightning.
Having seen him one enters upon immortality.
Inward-directed contemplation on the Highest is often deflected to outside objects. Unqualified understanding thus becomes qualified. But the happiness obtained when the mind is absorbed by God has only the Self as witness. That is Reality, the pure, the immortal, that is the goal, that certainly is the world!
If someone has the senses withdrawn as in sleep and a perfectly pure heart, he sees as if in a dream in the emptiness of the senses the substance, the Leader whose form is light, who is beyond sleep, old age, death, and sorrow.
Then that person himself becomes the one who is called substance, the Leader whose form is light, who is beyond sleep, old age, death, and sorrow.
Maitri Upanishad IX, 23-25
