Abhyasa means practice. What kind of practice? To regulate the mind. Sri Krishna says in the Bhagavad Gita (2:58):
Yadaa samharate chaayam kurmon-gaaneeva sarvashaha; Indriyaaneendriyaarthebhyastasya prajnaa pratishtthitaa.
Like a turtle which draws its limbs from all directions into its shell, a person should also withdraw all the senses from sense objects. Only then will the mind become steady.
This is the practice to be undertaken to harness the mental faculties. Sri Krishna says that the mind is connected to sense objects. It follows the senses wherever they go. Therefore, withdraw the mind from following the senses. If the eyes look at something pleasant, recognize it. At the same time, say, “Yes, it is beautiful, I appreciate it”, and stop there. Acknowledge it, accept it and stop there. Don’t crave it. Don’t be obsessed by it. The moment you begin to crave, you are obsessed by the need to possess something. If the ears hear something nice, acknowledge it, appreciate it, but don’t be attached to it. If the nose smells something nice, acknowledge it, appreciate it, but don’t hanker after it. In this way, you will gradually withdraw the mind from following the senses and creating more desires and expectations.
Right now, your mind is a slave to the senses. When the mind becomes a slave to the senses, the senses also become a slave to the mind. Both fuse into one. There is no distinction between a sense experience and a mental experience because at one point they come together and merge into one. If you look at something delicious to eat, your mind is desiring it. Your mind has merged with the desire, the vision, the expectation, the hunger, the taste, everything.
Remember, the mind and the senses are not two separate things, although they are spoken of as such. They are gross and subtle behaviours of the same shakti, the same power. The senses are the gross behaviour and the mind is the subtle behaviour of the same cosmic power. When the senses are active, the mind fuses with the senses and follows the senses all around. When the mind disassociates from the senses, as happens during sleep at night, it establishes itself independently of the sense experiences. The mind continues to exist, but the senses don’t exist.
In sleep, smells don’t bother you, visions don’t bother you, different sensations don’t bother you until and unless they become extreme. Only when they become extreme do they draw the mind out from its self-identification and into the outer gross dimension. At night you hear many sounds, but you are not disturbed by them. However, if the telephone rings you will be disturbed, as that extreme sound will draw the mind out from its own identification with deep sleep. Several mosquitoes can bite you while you are asleep and you will not even be aware of it until a delicate spot is touched, and then you will be forced to open your eyes and make yourself comfortable.
When the mind is established in its own identity, the senses have to become more powerful than the mind in order to draw it out. This is what happens during the sleep state. In the normal waking state, the senses and the mind act and function as one entity, one power, one experience. If the senses are withdrawn from the sense objects in the waking state as well, the mind will become still and established in itself. Sri Krishna has used the term prajna in this context, not manah. He says (2:58:2):
Tasya prajnaa pratishthitaa.
One (whose senses are withdrawn) is established in prajna.
Sri Krishna is indicating a specific faculty of the mind. Prajna is higher intelligence. It relates to the faculty of buddhi with which one decides upon joy OR sorrow, and which thus becomes the cause of agitation of the senses.
Objects of enjoyment will always exist. At the beginning of creation when life had not manifested, something existed. Human beings were not there, but objects were there. When human beings cease to exist and creation remains, objects will continue to exist. Creation is made of object and subject, while life is formed out of prana and relates to living beings. Even when there are no living beings, the objects and subjects of enjoyment will remain. Living beings come into creation to enjoy them, and when the time period for which they were meant to enjoy is over, they depart. Therefore, Sri Krishna’s words signify that sense objects will always exist, but you have to make the effort to withdraw the senses from them. Just as a tortoise withdraws its limbs, withdraw the mind. This is the abhyasa or practice that needs to be undertaken. The sequence indicated in the Bhagavad Gita is the sequence of raja yoga, which is expounded in the Yoga Sutras.