As I discuss in this answer, one of the early movements that was important in the development of Vaishnavism was the ancient Pancharatra movement, whose sacred texts consisted of detailed procedures to worship the sage Narayana, an ancient incarnation of Vishnu. Since the Pancharatra texts originated from Narayana himself, they are followed by pretty much all Vaishnavas today. But there was a time when some people, especially those of the Purva Mimamsa school, questioned the validity of the Pancharatra texts because they believed that the Vedas were the only legitimate Hindu scriptures. So as I discuss in this question, the early Sri Vaishnava Acharya Yamunacharya composed a work called the Agama Pramanya to defend the scriptural authority of the Pancharatra texts.
Now the Purva Mimamsa school believed that Vishnu was not competent to compose a scripture (!), because he wouldn' have the requisite knowledge to do so. So in this excerpt from the Agama Pramanya, Yamunacharya demonstrates the omniscience of Vishnu by quoting various scriptures which describe Vishnu as Paramatma or the supreme soul. In particular, he says this:
That He is the Supreme Soul we learn also from the statements of Dvaipayana [Vyasa], Parashara, Narada, and other great seers. Thus:
"Know thou, O tormentor of thy foes, that the entire world rests on Vishnu. The great Vishnu creates the totality of creatures, moving and unmoving. In him they go to their reabsorption, from Him they originate."
"The glorious sage Narayana, without beginning or end, is the sovereign Lord. He creates the creatures, those that stand still and those that move. That he is the supreme Brahman is also learnt elsewhere. Keshava, O best of the Bharatas, is the sovereign, the supreme soul, the entire universe: thus it stands revealed in many places of the scripture."
"For those who seek to know the supreme principle by many-sided reasonings Hari alone is the Principle, the great Yogin, Narayana the Lord."
My question is, what scriptures are these three quotes by sages from? The second one is probably from the Mahabharata, since it says "O best of the Bharatas", so it's probably someone addressing one of the Pandavas. And the first quote may also be from the Mahabharata, since it says "O tormentor of thy foes", so it's probably addressed to some king. Or they could be from the Srimad Bhagavatam, since it consists of a narration to Arjuna's son Parikshit. But where is the third quote from?
Does anyone recognize any of these quotes?
