The major religious and spiritual traditions tend to form around a somewhat common pattern as the elements required to achieve the result are similar regardless of the specific tradition involved. There is first of all a Dharma, a rule of life, a teaching, a form of guidance for living that is brought forth as a model for people to use to realize and embody the inspiration that has to manifest at the point in time that brings it forth. There is the group of people called to take up the teaching and make it real in their lives, whether this is called a fellowship, a congregation or a sangha. And there is a teacher or guide, someone who embodies the teaching, who shows the way, who guides and inspires, a Buddha or a Christ or a Krishna.
These are the general conditions for the manifestation of a new power of consciousness and way of life. The Avatar’s role is, as Sri Aurobindo explains: “The Avatar represents the third element, the divine personality, nature and being, who is the soul of Dharma and the sangha, informs them with himself, keeps them living and draws men towards the felicity and the liberation.”
The special role of the Avatar is to ensure that people are inspired by the force of the new teaching and the power of consciousness represented by it, that they see that it is possible to live and act under the impulsion of this force, and that it can and must remain a living force not constrained by custom or form, but able to respond to circumstances, adapt itself to life and provide a meaningful guidance and direction for life from a new standpoint with a real power of effectuation. Thus the Avatar is something of a catalyst for the descent and integration of a new power of consciousness in life.
Sri Aurobindo, Essays on the Gita, First Series, Chapter 17, The Divine Birth and Divine Works, pg. 164