Chapter 13 · The Field and the Knower · Krishna said
Bhagavad Gita 13.20 — Nature and Self are beginningless
प्रकृतिं पुरुषं चैव विद्ध्यनादी उभावपि। विकारांश्च गुणांश्चैव विद्धि प्रकृतिसम्भवान् ॥
prakṛtiṃ puruṣaṃ caiva viddhyanādi ubhāvapi | vikārāṃśca guṇāṃścaiva viddhi prakṛtisambhavān ||
Meaning
Know that both Prakriti (nature) and Purusha (the Self) are without beginning. Know also that all changes and the three qualities (gunas) are born of nature.