Sri Aurobindo
Letters of Sri Aurobindo
Volume 3
As regards Saraswati’s question – this is not a Yoga of bhakti alone; it is or at least it claims to be an integral Yoga, that is, a turning of all the being in all its parts to the Divine. It follows that there must be knowledge and works as well as bhakti, and in addition, it includes a total change of the nature, a seeking for perfection, so that the nature also may become one with the nature of the Divine. It is not only the heart that has to turn to the Divine and change, but the mind also – so knowledge is necessary, and the will and power of action and creation also – so works too are necessary. In this Yoga the methods of other Yogas are taken up – like this of Purusha-Prakriti but with a difference in the final object. Purusha separates from Prakriti, not in order to abandon her, but in order to know himself and her and to be no longer her 
plaything, but the knower, lord and upholder of the nature; but having become so or even in becoming so, one offers all that to the Divine. One may begin with knowledge or with works or with bhakti or with Tapasya of self-purification for perfection (change of nature) and develop the rest as a subsequent movement or one may combine all in one movement. There is no single rule for all, it depends on the personality and the nature. Surrender is the main power of the Yoga, but the surrender is bound to be progressive; a complete surrender is not possible in the beginning not only as a will to it in the being for that completeness, but – in fact it takes time; yet it is only when the surrender is complete that the full flood of the sadhana is possible. Till then there must be the personal effort with an increasing reality of surrender. One calls in the power of the Divine Shakti and once that begins to come into the being, it at first supports the personal endeavour, then progressively takes up the whole action although the consent of the sadhak continues to be always necessary. As the Force works, it brings in the different processes that are necessary for the sadhak, processes of knowledge, of bhakti, of spiritualised action, of transformation of the nature. The idea that they cannot be combined is an error.