That supreme original Personality of Godhead, Lord Śrī Kṛṣṇa, expanding His plenary portion as Mahā-Viṣṇu, the first incarnation, creates this manifested cosmos, but He is unborn. The creation, however, takes place in Him, and the material substance and manifestations are all Himself. He maintains them for some time and absorbs them into Himself again.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
विशुद्धं केवलं ज्ञानं प्रत्यक् सम्यगवस्थितम् । सत्यं पूर्णमनाद्यन्तं निर्गुणं नित्यमद्वयम्
viśuddhaṃ kevalaṃ jñānaṃ pratyak samyagavasthitam | satyaṃ pūrṇamanādyantaṃ nirguṇaṃ nityamadvayam
SB 2.6.39