The Tiruppavai is thirty verses long and it is heard every year in Tamil Vaishnava households and temples through the month of Margazhi, roughly mid December to mid January, one verse a day before dawn. The frame is a girls' vow: a young woman goes round waking her sleeping friends, one by one, so that they can bathe in the river in the cold early morning and keep the observance together, and the last houses she comes to are the god's.
The poem's power is in the ordinariness of its detail. There are buffaloes, drums, wet courtyards, lamps, a girl who will not get out of bed. The theology is never stated and is everywhere: the vow is for rain and prosperity in the conventional form, and it is plainly for God, and the poet never separates the two. Because it is short, metrical and unforced, it has stayed in oral circulation for eleven centuries without needing a commentary to survive.
Andal's second and longer work, the Nachiyar Tirumoli, is a different matter. It is direct, sensuous and painful, full of the longing of a woman for an absent lover who is also Vishnu, and it includes a sequence in which she sends the clouds and the birds as messengers to him. Sri Vaishnava commentators have read it allegorically for a thousand years. Modern readers have sometimes read it otherwise, and the argument about how to read it has occasionally become a public quarrel in Tamil Nadu.