Madhvaon Brahma Sūtra 1.1.30
Dvaita Vedānta
Sūtra
शास्त्रदृष्ट्यातूपदेशो वामदेववत्
śāstradṛṣṭyātūpadeśo vāmadevavat
Sūtra translation
The declaration is made only in reference to Sastra (the inner guide, by Indra) as by Famadeva.
Sastra means is the ruler within, the Lord Vishnu. The word Sastra is indeed so used in the Bhagavata pas- sage, “The knowledge, the Sastra (guide), the .final abode.” The Padmapurana says, “ Vishnu is declared by all the names of different things, for the reason that He rules all. There is no word whatever which names a thing without declaring Purushothama (the Lord of Lords). Like the declarations of Vamadeva “ I was Manu and Surya, etc.,” Indra’s speech is to be understood.