This is from Bhagavad-Gita, Chapter 6, texts 1-15.
Arjuna: Who is a real “yogi,” a real “renunciate”?
Krishna: A yogi and renunciate is someone who responsibly carries out their duties without being obsessed with what rewards it brings them. You don’t become a renunciate just by leaving your home, nor do you become a yogi just by having no job.
Arjuna: Is there a difference between being a “yogi” and being a “renunciate”?
Krishna: No, Arjuna. They are the same. No one can become a yogi without renouncing selfish motivations. The wise person who aspires to become a yogi is purified by working without selfish motivation. This practice eventually elevates us to the stage where we have no need for any normal work at all.
Arjuna: How do we know when we have attained that elevated stage?
Krishna: There will be no urge to work for any sensual pleasure. Then you will be a yogi without selfish motivation.
Arjuna: How would I make further progress within this elevated stage?
Krishna: It is all within the power of your own mind. You can elevate yourself by your thoughts, or degrade yourself. Your mind can be your friend or your enemy. If you have control of your mind, it is your friend. Otherwise it will work against you like an enemy.
Arjuna: What is it like to have “control over the mind”?
Krishna: Regardless of cold or heat, happiness or distress, honor or dishonor – in all situations you will feel very peaceful, and will be in touch with the divine soul. All your inner hungers will be understood and realized. You will dwell at the core of your being and be unaffected by sensual tribulations. To you, gold will just seem to be a rock; money, just paper. And this neutrality will eventually extend beyond objects to people, too. You will have equal regard for sweethearts and friends, as you do for enemies, neutrals, and mediators; for enemies as for friends; and even for the pious as for the sinful.
Arjuna: When a person at such an elevated stage, what duties does he or she perform?
Arjuna: How is it done?
Krishna: It is an effort to control the flow of thoughts in the mind without coming under their grip. The effort is to direct the flow of thoughts away from selfish desires and towards the spiritual. This practice must be done in thorough seclusion, alone.
Arjuna: Please say more about the proper location for meditation.
Krishna: It should be in a sanctified place. You should make a place to sit that is a little bit raised off the ground, out of kuśa grass covered with deerskin, covered by cloth. Sit there with good, steady posture, and practice directing the flow of your thoughts to a single point; curtailing your external sensual activities. This practice will make your soul very clear.
Arjuna: Can you elaborate on the “steady posture”?
Krishna: Hold your torso, neck and head straight, balanced, firm and steady.
Arjuna: What about “curtailing the senses”?
Krishna: Restrain your perception from wandering here and there; focus your eyes on the tip of your nose and don’t look elsewhere.
Arjuna: How can the mind’s flow be controlled?
Krishna: Follow the brahmacārī path: pursue no lusts. Then you will be peaceful. You must practice giving up all fears. Then your mind will come under your control.
Arjuna: When I have my mind under my own control, what should I do with it?
Krishna: Seat me within your pure mind! Make me your ultimate goal.
Arjuna: What is the result of this practice?
Krishna: Dedicating your heart and soul constantly and regularly to this practice, you will attain the supreme śānti (peace): nirvāṇa (liberation) and come to my position.