arjuna uvāca
saṃnyāsaṃ karmaṇāṃ kṛṣṇa punar-yogaṃ ca śaṃsasi |
yac-chreya etayor-ekaṃ tan-me brūhi suniścitam || 1 ||
In the last three Chapters, Bhagvan Shri Krishna explained Arjuna the subtle concepts of Sanyasa(Renunciation of fruitful activities), the soul, rebirth, the Yajna, the Jnana and Karma Yoga. Among the all concepts explained two are Sanyas and Karmayoga. The literal meaning of Sanyas is to renounce the actions and Karma yoga means to engage in action. Arjuna could not understand how two can be true at the same time. If at all both are true then which one is better.
He, therefore, expresses his confusion to Bhagvan Shri Krishna and asked for guidance in the above shloka.