Explanation:

The Nalayira Divya is a collection of 4,000 Tamil verses (Naalayiram in Tamil means 'four thousand') composed by the 12 Alvars, and was compiled in its present form by Nathamuni during the 9th – 10th centuries.
The work, an important liturgical compilation of the Tamil Alvar Bhaktas, marks the beginning of the canonization of 12 Vaishnava poet saints, and these hymns are still sung extensively today. The works were lost before they were collected and organized in the form of an anthology by Nathamuni.
It was frequently described as the Tamil Veda, thus claiming that the text was as significant as the four Vedas in Sanskrit that were cherished by the Brahmanas.