Arjuna said: O Keshava, I wish to know about material nature (prakriti), the enjoyer (purusha), the field, the knower of the field, knowledge and the object of knowledge.
Bhagavad Gita - Chapter 13 - Prakrti Purusha Viveka Yoga - The Yoga of Differentiation Between Matter and Consciousness
Bhagavan Shri Krishna replied: O son of Kunti, this body is known as the field and one who knows this field is said by the wise to be the knower of the field.
You should know that I am the knower of all fields, O descendent of Bharata. I consider the knowledge of the field and its knower to be real knowledge.
Now hear from Me in brief about what that field is, what constitutes it, what are its transformations, its origin and who is the knower of the field and what is his influence.
This knowledge has been sung of in many different ways by different sages, by the Vedas, and is found in the logically conclusive chapters of the Vedanta-sutras.
The main elements are the false ego, intelligence, the unmanifest material nature, the ten senses, the mind, the five sense-objects, desire, hate, pleasure, pain, the gross body, consciousness and determination. All these elements that are described here are considered to be the field.
Desirelessness, humility, nonviolence, tolerance, simplicity, service to the spiritual master, purity, steadiness, selfcontrol, detachment from sense gratification, absence of false ego, perception of the miseries of birth, death, old age and disease, detachment, freedom from attachment to wife, children and household life, perpetual equanimity in both happy and distressful circumstances, constant and firm devotion unto Me, dwelling in a solitary place, free from the desire to socialize with the masses, constant determination in achieving self-realization and a desire to gain knowledge of the Absolute Truth – all these qualities have been declared to be knowledge. Anything contrary to this is ignorance.
I shall now explain the object of knowledge, knowing which one attains immortality. It is subordinate to Me and is the eternal Supreme Brahman that is beyond material cause and effect.
His hands and feet are everywhere. His eyes, heads and mouths are everywhere. His ears are everywhere. Thus He exists, pervading all things.
He illuminates all the senses and their functions, however He is devoid of any material senses Himself. He remains detached and He is the Maintainer of all. Although He is devoid of all material qualities, He is the Master of all qualities.