Those who, taking refuge in Me, strive to be free of the torments of old age and death, come to know the Brahman, the supreme Reality, all about adhyātma (nature of spiritual Self), and the truth about cosmic activity in its entirety.
Krishna, true to his position and role as a spiritual Teacher, imparts a good deal of knowledge allied to spiritual seeking and the seeker. This is how he brings factors and subjects commonly discussed by spiritual thinkers and disseminated by exponents, in the context of spirituality. The personal spiritual sādhanā is the direct means to realize the supreme Truth. It bestows contentment and fulfilment, dispelling all doubts and delusion.
He first speaks of Brahman, the supreme Reality, the first and the last word in spiritual science. Next he refers to adhyātma, the experiential presence in everyone’s body, in every life form. Then he brings karma, the cosmic activity, the very characteristic of creation, Nature, described earlier (3.5, 3.16). All form a part of his extended exposition.
Krishna says, those who strive hard with attention, taking total refuge in him, they come to know the essence of all these concepts.