The Azhwars were blessed by Lord Narayana with both bhakti and gnana, and their God love poured forth through their verses.
Vaishnavite Acharyas, who came later, wrote commentaries on these verses. Manavala Mamunigal wrote about the Acharyas who were his predecessors.
He wrote Acharya Hridayam when he was old and ailing. His disciple asked him why he troubled himself so to write. Manavala Mamunigal replied that he was taking the effort not for his disciples, but for future generations.
In other words, he considered the work to be important, to instruct future generations. Such was the mercy Manavala Mamunigal had for mankind. Mercy is the primary quality an Acharya should have, elaborated Kidambi Narayanan, in a discourse.
An Acharya must have gnana and also must adhere to what he preaches. If the Acharya himself lacks gnana, can he guide his disciples? Suppose two boats are traversing a river. One boat springs a leak, and water begins to get in slowly. Alarmed, those in this boat call out to those in the other boat for help.
Unfortunately, the other boat is also on the verge of sinking. So how can those in the second boat help those in the first boat? Similar would be our plight if we sought instruction from an acharya who himself lacks gnana. The Acharya must have paripoorna gnana (complete knowledge.)
There are Acharyas who instruct their disciples, when the latter make a request for such instruction. There are yet others, who, out of their merciful nature, take pity on the disciples and instruct them, without even being asked to. Sometimes, a disciple may not be deserving of upadesa. In such cases, the Acharya corrects him, and then instructs him, so that he becomes deserving of the advice given to him.
An Acharya must never think that he is himself offering upadesa to his disciple. He must give credit to his own preceptor and say that it is his preceptor who is preaching through him. He must never offer upadesa in the hope of receiving monetary rewards.
Keywords: Lord Narayana