With the development of the ego-consciousness, the force of desire acquires a nexus around which to build its influence and awaken or reawaken desire on the physical and psychic Prana, even if they have been more or less eliminated through the purification process. this provides the seeker with an interesting and difficult internal review, analysis and line of action, to overcome this “spiritual seed” of desire. As long as the individual is completely aligned with the transcendent and universal aspects of existence, there is the possibility of desireless action; however, once the individual has taken on an individual role, it becomes much harder to ensure that action is desireless and instrumental of the divine will, rather than a subtle expression of individual bias, personal desire or any form of self-aggrandisement.
Sri Aurobindo describes the issue: “But the moment the individual soul leans away from the universal and transcendent truth of its being, leans towards ego, tries to make this will a thing of its own, a separate personal energy, that will changes its character: it becomes an effort, a straining, a heat of force which may have its fiery joys of effectuation and of possession, but has also its afflicting recoils and pain of labour. It is this that turns in each instrument into an intellectual, emotional, dynamic, sensation or vital will of desire, wish, craving. Even when the instruments per se are purified of their own apparent initiative and particular kind of desire, this imperfect Tapas may still remain, and so long as it conceals the source or deforms the type of the inner action, the soul has not the bliss of liberty, or can only have it by refraining from all action; even, if allowed to persist, it will rekindle the pranic or other desires or at least throw a reminiscent shadow of them on the being. This spiritual seed or beginning of desire too must be expelled, renounced, cast away: the the Sadhaka must either choose an active peace and complete inner silence or lose individual initiation…in a unity with the universal wil, the Tapas of the divine Shakti. The passive way is to be inwardly immobile, without effort, wish, expectation or any turn to action…; the active way is to be thus immobile and impersonal in the mind, but to allow the supreme Will in its spiritual purity to act through the purified instruments. Then, if the soul abides on the level of the spiritualised mentality, it becomes an instrument only, but is itself without initiatve or action…. But if it rises to the gnosis, it is at once an instrument and a participant in the bliss of the divine action and the bliss of the divine Ananda; it unifies in itself the prakrti and the purusa.
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 8, The Liberation of the Spirit, pg. 649