According to Sri Vaishnava Agamas, Vishnu has five aspects or modes. They are para, vyuha, vibhava, antaryami and archavatara. The fifth form
of Lord Vishnu, Archa Avatara (image manifestation), is very easily accessible
and visible to all. Archa Avatara is the murti form (picture, painting,
sculpture and other forms visible by human eye).
Since we cannot worship para, vyuha, vibhava and antaryami
forms, which can only be imagined and meditated upon, and since they are beyond
our reach, Acharyas point out Archa Avatara alone suits the devotees most.
The image form of Lord Vishnu becomes divine the moment it
is installed by great acharyas according to the rules laid down in the Agamas.
In Archa Avatara form, God receives prayers from devotees
and grants their prayers and blesses them.
Alvars have sung in praise of archa forms in 108 religious
places (108 Divya Desams).
Nalayira Divya Prabandham (four thousand divine collections)
are the poetic descriptions of God.
Temples are replicas of the human body. Archa Avatara in the
sanctum sanctorum in the temples reminds us of the truth that God is seated in the
heart of each individual.