[1] Written in simple Malayalam, the Jnanappana was Poonthanam's magnum opus and is an important work of Bhakti literature from Kerala and is revered for its poetic merit and intensity of devotion.The Jnanappana is noted for its literary quality, the use of simple phrases, its philosophical strength and reflects Poonthanam's deep bhakti to Guruvayoorappan.[4] In the Jnanappana, Poonthanam Namboothiri, an ardent devotee of Shri Guruvayurappan, transforms his unbearable sorrow from his infant son's death into a yogavishesham.The line "unnikrishnan manasil kalikumbol, unnikal mattu venamo makkalai" (When the baby Krishna plays in one's mind, does one need one's own children?)Even though the language is very simple, Jnanappana, or song of wisdom deals within it with the essence of the Srimad Bhagavatam, Bhagavad Gita, Bhajagovindam, Viveka Chudamani and Narayaneeyam.