In the Yoga of knowledge, one of the steps is to identify with the self-aware internal witness consciousness, and thereby to observe the working of the nature of mind-life-body from a separate, uninvolved standpoint. This stage is important to liberate the consciousness from total submission to the desires and limitations of the outer nature. For the seeker of self-perfection, this obviously is not the final goal but a transitional stage. When the witness awareness is established firmly, it becomes necessary to begin to exercise the power of sanction over the actions of the outer nature, and from there, the power of mastery.
Sri Aurobindo explores the relation between the need for self-surrender to the Divine with the development of spiritual self-mastery: “At first it may not be apparent how this ideal of active self-mastery can be reconciled with the apparently opposite ideal of self-surrender and of becoming the assenting instrument of the divine Shakti. But in fact on the spiritual plane there is no difficulty. The Jiva cannot really become master except in proportion as he arrives at oneness with the Divine who is his supreme Self. And in that oneness and in his unity with the universe he is one too in the universal self with the will that directs all the operations of Nature. But more directly, less transcendentally, in his individual action too, he is a portion of the Divine and participates in the mastery over his nature of that to which he has surrendered himself. Even as instrument, he is not a mechanical but a conscious instrument. On the Purusha side of him he is one with the Divine and participates in the divine mastery of the Ishwara. On the nature side of him he is in his universality one with the power of the Divine, while in his individual natural being he is an instrument of the universal divine Shakti, because the individualised power is there to fulfil the purpose of the universal Power. The Jiva, as has been seen, is the meeting-place of the play of the dual aspect of the Divine, Prakriti and Purusha, and in the higher spiritual consciousness he becomes simultaneously one with both these aspects, and there he takes up and combines all the divine relations created by their interaction. This it is that makes possible the dual attitude.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 17, The Action of the Divine Shakti, pp. 739-740