Chapter 3: Karma Yoga, Yoga of Action
In this Arjuna recognizes that he wants to attain Moksha, Liberation, enlightenment, and nothing less and asks Krishna why he should take part in war instead of taking the path of Sanyasa or renunciation.
In the third chapter, Krishna explains the nature of Karma and asks Arjuna to fulfill his Dharma and take part in the war without desiring the fruits (niskam karma). Here Krishna explains the nature of desires and likes and dislikes.
Verse 5: Indeed no one ever exists for even a second without performing action because everyone, being helpless, is made to perform an action by the gunas (tamas, rajas, and sattva) born of prakriti.