The instrument that is chosen for this Yoga is neither intellect nor emotion. Intellect is the chosen instrument of Jnana yoga. The instrument chosen for Bhakti yoga is emotion. But the instrument chosen for Karmayoga is ‘will’. But since this Karmayoga is an integral Karmayoga, the Karmayoga of the Bhagavad Gita is not merely a Karmayoga but an integral Karmayoga, therefore, although predominance is the will, intellect is also an instrument, emotion is also an instrument, and will is the chosen predominant instrument, but ultimately you will find that by using that instrument, gradually you will also bring into picture the intellect and emotion. So that ultimately all the three are united, and then it becomes an integral Karmayoga. These are the three instruments of integral Karmayoga, although Karmayoga as such has his own emphasis on will: that is the instrument.
What is the method? The method of Karmayoga is to purify the will. Purification is always the first starting point of any method of Yoga, depending upon the instrument. If Jnanayoga is the method, is the instrument that intellect is to be purified. In the case of Bhaktiyoga, emotion is to be purified. In the case of Karmayoga, will is purified. The emphasis falls upon the purification.
In every Yoga, there are three basic processes: purification, concentration and renunciation. No Yoga can be accomplished without these three: there has to be a purification; there has to be a concentration; and there has to be renunciation.
In the case of Karmayoga, there is first the purification of the will, and you will see in this chapter when we read further, 2nd chapter and 3rd chapter particularly, how much emphasis is laid upon purification. Then there is concentration. Why Sri Krishna emphasises so much in the 2nd chapter on the concentration of Buddhi? And by Buddhi is meant not only intellect, but intellect that guides the will. That is the meaning.
There is an emphasis upon concentration of the will. He says that, “vyavasāyātmikā buddhi”: the Buddhi which is engaged, which is concentrated. The entire description of sthitaprajña, which takes a large portion of the closing part of the chapter two is devoted to sthitaprajña: so, sthita prajña, the one whose prajña is sthita; one whose intelligent will is stable, is concentrated. Concentration is also a part of Karma yoga: concentration of will. That is why the word that is used is yuktaḥ: one whose will is concentrated.
There is a great emphasis upon the purification. Then there is emphasis upon the concentration of the will, and then, there is a lot of discussion on the subject of renunciation: tyāga, sannyāsa. You will find these two words often coming in these 3, 4 chapters; it is a question of renunciation.