When Koorathazhvan was in Srirangam at the feet of Ramanuja, his family needs were taken care of by what he collected as biksha daily. One day due to heavy rains, he was unable to go to the streets and as such he and his wife, Andal, had to go without food that day.
That night, thinking of Thiruvaimozhi as his food, Koorathazhvan went to bed. At that time, the sound of the aravaNai prasAdam being presented to Lord Ranganatha inside the temple was heard. Hearing it, Andal thought to herself “O Lord! While your devotee, Sri Kooratthazhvan, is going without food, is it appropriate that You enjoy the same?”
Immediately, Lord Ranganatha ordered Utthama Nambi to take the aravaNai prasAdam to Kooratthazhvan’s home.
Koorathazhvan was shocked to see Utthama Nambi come to his home late in the night with the prasadam. When he enquired about it, Utthama Nambi informed him that it was brought upon the command of the Lord Himself.
Accepting the prasadam from the Lord, Koorathazhvan gave one part to his wife and took one for himself.
Just as Dasaratha gained his children from the prasAdam of the putrakAmEshti yAga, so too from the prasAdam of the Lord, Koorathazhvan and Andal had twins – Parasara Bhattar and Veda Vyasa Bhattar – on Vaikashi Anusham, the day after Nammazhvar’s thirunakshatram.Article taken from site www.acharya.org