Question
Why isn’t Lord Ayyappa an avatar of Lord Mahavishnu?
Answer
The difference between a descended avatāra and a foolish embodied being (dehī) is that avatāra does not forget his spiritual identity in the process and maintains a strong connection with the spiritual plane. E.g. in the Kurukšētra battle Krišna was hit by all kinds of divine weapons, including one that Arjuna could not possibly deflect, but Krišna did not suffer. He could just absorb the weapons, himself being unarmed. Likewise, any avatāra is expected to manifest at least some exceptional supernatural prowess.
In Chaitanya-Charitāmrita 2.20.365 Sanātana Goswāmī asks a tongue-in-cheek question "Who is the avatāra in Kali age?". The question is amusing, because he is asking it to that avatāra himself and they both know that. However, the Master answers:
“O Sanātana, give up your intelligent tricks. Listen to the description of the šaktyāveša-avatāras.
To summarize his answer, an avatāra is recognized by the principal (mukhya) and superimposed (gauna) symptoms. In an avatāra, the manifestation of (divine) energy is direct (sākšāt-šaktye), if it is just a semblance (ābhāse), the person is called "vibhūti" instead. The symptoms to be looked for are described in the šāstras by muni Vjāsa (primary symptoms: name, skin color, dress, place of residence; divine energies: knowledge, love, the powers to create and maintain worlds and to protect and destroy villains; superimposed activities: killing of demons, creation, maintenance and destruction of the worlds and other). He also goes on to mention some avatāras and to describe the qualities and pastimes of Krišna in detail.
Thus,
while we have not discovered a description in šāstras of Lord Ayyappa as an avatar of Lord Mahavishnu, we cannot accept him as such.
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