The Personality of Godhead, the master of all living entities, existed prior to the creation as one without a second. It is by His will only that creation is made possible and again everything merges in Him. This Supreme Self is symptomized by different names.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
भगवानेक आसेदमग्र आत्माऽऽत्मनां विभुः । आत्मेच्छानुगतावात्मा नानामत्युपलक्षणः
bhagavāneka āsedamagra ātmā''tmanāṃ vibhuḥ | ātmecchānugatāvātmā nānāmatyupalakṣaṇaḥ
SB 3.5.23