Chapter 6, Verse 2
Part of 6: Dhyān Yog — ध्यानयोगयं संन्यासमिति प्राहुर्योगं तं विद्धि पाण्डव। न ह्यसंन्यस्तसङ्कल्पो योगी भवति कश्चन॥
yaṁ sannyāsam iti prāhur yogaṁ taṁ viddhi pāṇḍava na hyasannyasta-saṅkalpo yogī bhavati kaśhchana
Do you, O Arjuna, know that Yoga is what they call renunciation; no one indeed becomes a Yogi who has not renounced their thoughts.
Sankalpa is the working of the imagining faculty of the mind that makes plans for the future and guesses the results of plans so formed. No one can become a Karma Yogi who plans and schemes and expects fruits for his actions. No devotee of action who has not renounced the thought of the fruits of his actions can become a Yogi of steady mind. The thought of the fruits will certainly make the mind unsteady. Lord Krishna eulogises Karma Yoga here because it is the means or an external aid (Bahiranga Sadhana) to Dhyana Yoga. Karma Yoga is a steppingstone to Dhyana Yoga. It leads to the Yoga of Meditation in due course. In order to encourage the practice of Karna Yoga it is stated here that Karma Yoga is Sannyasa. (Cf. V.4)