This, as told, is the wisdom of the Self. Hear now the wisdom of yoga, equipped with which, O Partha (Arjuna), you will cut asunder the bondage of karma (action).
Arjuna is in Kurukshetra to fight the war. Krishna stresses that there is no question of escaping from it.
But what Krishna straightaway exposed is the core of spiritual wisdom, the immortal nature of the Soul, the ‘I’ identity of everyone. Wisdom can be pursued only by the intelligence. That requires a certain seclusion and inner absorption, for which Arjuna and those like him will not have opportunity at all. So Krishna has to present an alternate pursuit coupled with activity. That alone will be suitable and practical for the people of the world.
Krishna thus shifts from the wisdom pursuit, Sānkhya yoga, to the pursuit of actions, Karma-yoga. But he underscores both as verily pursuits of the intelligence. Either it is nurturing the Soul-buddhi, as in Sānkhya, or Yoga-buddhi, as in Karma-yoga. Both equally enrich and elevate the seeker, leading him to the Self. Which pursuit is suited to a seeker will depend on his fitness.