When we once acknowledge that we are not separate, distinct and fragmented beings, but part of a great universal energy of manifestation, it becomes easier to understand and accept the concept that all action is undertaken by sacrifice, and that aligning ourselves with that action and its basis in sacrifice is the true path of liberation. Sri Aurobindo emphasizes this: “Sacrifice is the law of the world and nothing can be gained without it, neither mastery here, nor the possession of heavens beyond, nor the supreme possession of all; ‘this world is not for him who doeth not sacrifice, how then any other world?’
It is necessary not just to accept this as a concept, but to actually have this understanding permeate all our experience and actions. Sri Aurobindo describes the required effort: “The one thing needful, the saving principle constant in all these variations, is to subordinate the lower activities, to diminish the control of desire and replace it by a superior energy, to abandon the purely egoistic enjoyment for that diviner delight which comes by sacrifice, by self-dedication, by self-mastery, by the giving up of one’s lower impulses to a greater and higher aim.”
Once one is identified with the supreme consciousness of the Brahman, and the work done is recognized as being part of that vast universal energy that has been set in motion, we lose the sense of being a separated individual “doer” and the energy is freely given to the purposes of the universal manifestation. At that point, there is no individual that has desire, or that is frustrated with the lack of fulfillment of desire, and we have achieved “the one thing needful”.
Sri Aurobindo, Essays on the Gita, First Series, Chapter 12, The Significance of Sacrifice, pp. 114-115
Sri Aurobindo Studies 