Knowledge in a sheath of ignorance
The Purana identifies the sword with vidya and the scabbard with avidya.


Nandaka is the sword of Vishnu. The Vishnu Purana explains it as vidya, true knowledge, sheathed in the scabbard of ignorance. Vishnu is called Nandaki in the Vishnu Sahasranama, and the Tirumala tradition holds the poet Annamacharya to be an embodiment of the sword.
The texts tell different stories.
The Purana identifies the sword with vidya and the scabbard with avidya.
Annamacharya (1408-1503), the composer of the Venkateswara songs, is held to be born from a portion of Nandaka.