Traditionally, the Yoga of devotion has been seen as separate from the Yoga of knowledge, and as leading to a different resolution of the spiritual quest. The integral Yoga of Sri Aurobindo acknowledges that each traditional path of Yoga has its own starting point based in different aspects of the human being, but at a certain point in the process, each path can merge into a more comprehensive approach and bring forth the fruits of the other paths.
Sri Aurobindo describes the development of knowledge from a starting point of devotion: “That which in the end contains, takes up or unifies them all, is the relation of lover and beloved, because that is the most intense and blissful of all and carries up all the rest into its heights and yet exceeds them. He is the teacher and guide and leads us to knowledge; at every step of the developing inner light and vision, we feel his touch like that of the artist moulding our clay of mind, his voice revealing the truth and its word, the thought he gives us to which we respond, the flashing of his spears of lightning which chase the darkness of our ignorance. Especially, in proportion as the partial lights of our mind become transformed into lights of gnosis, in whatever slighter or greater degree that may happen, we feel it as a transformation of our mentality into his and more and more he becomes the thinker and seer in us. We cease to think and see for ourselves, but think only what he wills to think for us and see only what he sees for us. And then the teacher is fulfilled in the lover; he lays hands on all our mental being to embrace and possess, to enjoy and use it.”
Sri Aurobindo, The Synthesis of Yoga, Part Three: The Yoga of Divine Love, Chapter 8, The Mystery of Love, pp. 576-577
Sri Aurobindo Studies 
Pranam Maa.