The Sankhya and the Yoga Systems are eternal. All the Vedas, again, O king, are eternal. The Rishis, in all these systems or religion, have said that this universe existing from ancient times is Narayana's self.
सांख्यं च योगं च सनातने द्वे वेदाश्च सर्वे निखिलेन राजन्। सर्वैः समस्तैर्ऋषिभिर्निरुक्तो नारायणो विश्वमिदं पुराणम्॥