There are three ways in which we can serve Lord Narayana. We can serve using the body and this is kaya kainkaryam. We can serve through our words, and this is vaacha kainkaryam. Serving Him through our thoughts is maanaseeka kainkaryam.
Andal, in Her Tiruppavai, talks about all three types of service, said Kidambi Narayanan in a discourse. In the Kanaithilam verse, She talks of service using the body. The cowherds of Gokula were busy following Lord Krishna and forgot to milk the buffaloes at the appropriate time. The udders of the buffaloes were full of milk and when the buffaloes thought of their calves, the milk in their udders flowed out through the teats. It was the cowherd’s duty to milk the buffaloes. But he was engaged in a higher duty, namely service to God, resulting in his being away from the cows and buffaloes under his care.
Throughout Tiruppavai, Andal calls out to the Lord through His many names and describes His miraculous deeds and His avataras through Her verses. She thus shows the importance of vaacha kainkaryam.
In fact in one verse, She calls upon the Gopikas to sing of Him and to think of Him. And this thinking of Him is maanaseeka kainkaryam.
Andal’s Tiruppavai is, thus, a work that shows us how to serve the Supreme One so that we may attain moksha. While other Azhvars, like Nammazhvar and Tirumangaiazhvar, had imagined themselves to be nayakis pining for their nayaka, Lord Narayana, Andal’s Tiruppavai was a more emotional outpouring than theirs, for Andal did not have to make any effort to think like a woman in love. She was a woman in love with the Lord. Her love for Krishna is manifest in Her works. Ramanuja said, therefore, that none but Andal could explain Tiruppavai, capturing its meaning entirely.