My dear Lord, the original puruṣa-avatāra, Mahā-Viṣṇu, acquires His creative potency from You. Thus with infallible energy He impregnates material nature, producing the mahat-tattva. Then the mahat-tattva, the amalgamated material energy, endowed with the potency of the Lord, produces from itself the primeval golden egg of the universe, which is covered by various layers of material elements.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
त्वत्तः पुमान् समधिगम्य यया स्ववीर्यं धत्ते महान्तमिव गर्भममोघवीर्यः । सोऽयं तयानुगत आत्मन आण्डकोशं हैमं ससर्ज बहिरावरणैरुपेतम्
tvattaḥ pumān samadhigamya yayā svavīryaṃ dhatte mahāntamiva garbhamamoghavīryaḥ | so'yaṃ tayānugata ātmana āṇḍakośaṃ haimaṃ sasarja bahirāvaraṇairupetam
SB 11.6.16