Chapter VI Sloka12

tÇEka¢< mn> k«Tva yticÄeiNÔyi³ya>,
%pivZyasne yuÁJya*aegmaTmivzuÏye.

tatraik˜graÕ mana× k®tv˜ 
yatacittendriyakriy˜× |
upaviþy˜sane yuñjy˜d
yogam˜tmaviþuddhaye ( 6|12)||

There, having made the mind one-pointed, with the actions of the mind and the senses controlled, let him, seated on the seat, practise Yoga for the purification of the self.
Commentary: The self means the mind. The real Supreme Self is the Atma. This is Primary (Mukhya). Mind also is the self. But this is used in a secondary sense (Gauna). Mukhya Atma is Brahman or the highest Self. Gauna Atma is the mind.
Make the mind one-pointed by collecting all its dissipated rays by the practice of Yoga. Withdraw it from all sense-objects again and again and try to fix it steadily on your Lakshya or point of meditation or centre. Gradually you will have concentration of the mind or one-pointedness. You must be very regular in your practice. Only then will you succeed. Regularity is of paramount importance. You should know the ways and habits of the mind through daily introspection, self-analysis or self-Examination. You should have a knowledge of the laws of the mind. Then it will be easy for you to check the wandering mind. When you sit for meditation, and when you deliberately attempt to forget the worldly objects, all sorts of worldly thoughts will crop up in your mind and disturb your meditation. You will be quite astonished. Only thoughts that you entertained several years ago, and old memories of past enjoyments will bubble up and force the mind to wander in all directions. You will find that the trap-door of the vast subconscious mind is opened or the lid of the storehouse of thoughts within is lifted up and the thoughts gush out in a continuous stream. The more you attempt to still them, the more they will bubble up with redouble force and strength.
Be not discouraged. Nil desperandum. Never despair. Through regular and constant meditation you can purify the subconscious mind and its constant memories. The fire of meditation will burn all thoughts. Be sure of this. Meditation is a potent antidote to annihilate the poisonous worldly thoughts. Be assured of this.
Meditation on the immortal Self will act like a dynamite and blow up all thoughts and memories in the conscious mind. If the thoughts trouble you much, do not try to suppress them by force. Be a silent witness as in a bioscope. They will subside gradually. They try to root them out through regular silent meditation.
During introspection you can clearly observe the rapid shifting of the mind from the one line of thought to another. Herein lies a chance for you to mould the mind properly and direct the thoughts and the mental energy in the divine channel. You can rearrange the thoughts and make new associations on a new Sattvic basis. You can throw out worldly and useless thoughts. Just as you remove the weeds and throw them out, you can throw these out, and you can cultivate sublime, divine thoughts in the divine garden of your mind. This is very patient work. This is a stupendous task indeed. But for a Yogi of determination who has the grace of the Lord and an iron will it is nothing.
Calm the bubbling emotions, sentiments, instincts and impulses gradually through silent meditation. You can give a new orientation to hour feelings by gradual and systematic practice. You can entirely transmute your worldly nature into divine nature. You can exercise supreme control over the nerve-currents, muscles, the five sheaths (of the Self), emotions, impulses and instincts through meditation.