From the agitation of the original modes within the unmanifest material nature, the mahat-tattva arises. From the mahat-tattva comes the element false ego, which divides into three aspects. This threefold false ego further manifests as the subtle forms of perception, as the senses and as the gross sense objects. The generation of all these is called creation.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
अव्याकृतगुणक्षोभान्महतस्त्रिवृतोऽहमः । भूतमात्रेन्द्रियार्थानां सम्भवः सर्ग उच्यते
avyākṛtaguṇakṣobhānmahatastrivṛto'hamaḥ | bhūtamātrendriyārthānāṃ sambhavaḥ sarga ucyate
SB 12.7.11