When we try to understand the manifestation of the Avatar from the point of view of Nature, we can see in the outer form and action certain indications of this action. The Avatar is the leading and representative power of his age, representing enhanced power of knowledge, love, action or energy of whatever type is required at that time in the human growth and progress. The Gita raises, in this context, the concept of the Vibhuti, which is the intensity and preeminence of any specific power or quality. Sri Aurobindo describes it thus: “The Divine manifests himself through infinite qualities of his nature and the intensity of the manifestation is measured by their power and their achievement. The vibhuti of the Divine is therefore, impersonally, the manifest power of his quality, it is his outflowing, in whatever form, of Knowledge, Energy, Love, Strength and the rest; personally it is the mental form and the animate being in whom this power is achieved and does its great works. A pre-eminence in this inner and outer achievement, a greater power of divine quality, an effective energy is always the sign. The human vibhuti is the hero of the race’s struggle towards divine achievement, the hero in the Carlylean sense of heroism, a power of God in man.”
This intensity plays an important role: “This heightening of the powers of the being is a very necessary step in the progress of the divine manifestation. Every great man who rises above the average level, raises by that very fact our common humanity; he is a living assurance of our divine possibilities, a promise of the Godhead, a glow of the divine Light and a breath of the divine Power.”
By its nature, the manifestation of an Avatar into human form is also a Vibhuti, but not every Vibhuti is an Avatar! The Avatar, the divine direct manifestation to further the effort of human development, obviously carries within itself enhanced powers. There also needs to be a self-exceeding of the human growing into a divine nature, and those leading that effort manifest enhanced powers of consciousness and action in some specific form.
Sri Aurobindo, Essays on the Gita, First Series, Chapter 16, The Process of Avatarhood, pp. 151-152