Baba gave the following explanation to the mandali about the difference between the Avatar and the Perfect Masters:
Every God-Realized personality is perfect. However, those who come down and act as Masters – the Sadgurus and Avatar – come down with their minds universal and use divine powers to work for others. There is a place, Vidnyan Bhumika, where the Masters work and rest. It is similar to a threshold in between two places, where they can manage works both for the higher and lower worlds. One aspect is the preparation of souls from the lower world and the deliverance of them to the higher world, eventually realizing them. The Masters come down with the special purpose of bringing ripe souls to the highest state.
When the Perfect Masters come down with this duty to the world and work every day with the people of the world, they descend with universal mind. Through the universal mind, they take upon themselves the sins (bad sanskaras) of the ripe souls and thereby suffer themselves. They experience bliss through the soul and suffering through the mind. They enjoy the bliss through the soul, which is one with the Almighty, and bear the universal suffering through their universal mind.
The one who manifests as the Avatar has to give a spiritual push to the whole world. This is greater than the circle preparation work which all Sadgurus have to perform. This great push is the main difference in their duties.
Besides this difference, the Avatar is always perfect in all respects, spiritually as well as materially, and in particular, physically. The Avatar always has a charming personality with a beautiful, symmetrical face and body, while the Perfect Masters are generally of odd size and shape physically, with certain defects sometimes so abhorrent that one does not even like to look at them.
Christ, Muhammad, Zarathustra, Buddha, Ram and Krishna were Avatars and hence had charming personalities. So is mine.
-www.lordmeher.org, p1125
December, 1929; Nasik