The Rahasyatraya Sara is a work by the Sri Vaishnava Acharya Vedanta Desikan, concerning the meaning of the Rahasya Traya or three secrets of the Sri Vaishnava sect (of which I'm a member). (One of these secrets is the Dvaya mantra used to surrender to Vishnu, which I discuss here.) In this excerpt from the Rahasyatraya Sara, Vedanta Desikan discusses how the Jiva benefits from having a guru:
His gurus reveal to the Jiva the intimate relation existing between him and Narayana, the Lord of Lakshmi, who rules with his scepter the earth surrounded by the turbulent ocean and the world of Vaikunta without even the least exception. Do not the shastras say "The soul is neither God nor man, neither beast nor tree. Its essential nature is knowledge and bliss and it is entirely dependent on the Supreme Being and exists solely for his purposes (Sesha)" and again "The souls are indeed servants by nature of the supreme Supreme Being"?
The second quote is from verse 11 of the Mantra Raja Pada Stotram, a hymn to Narasimha from a Pancharatra text called the Ahirbudhnya Samhita. (See my answer here for more information on the Pancharatra texts.)
But my question is, what scripture does the first quote come from, the one which says "The soul is neither God nor man..."? It seems like an interesting quote, so I'd like to see the passage it's from.
Are there any commentaries on Vedanta Desikan's work who address this?