Bhagavad Gita 10.15
स्वयमेवात्मनात्मानं वेत्थ त्वं पुरुषोत्तम। भूतभावन भूतेश देवदेव जगत्पते।।10.15।।
svayamevātmanātmānaṃ vettha tvaṃ puruṣottama| bhūtabhāvana bhūteśa devadeva jagatpate||10.15||
svayamevatmanatmanam vettha tvam purushottama bhutabhavana bhutesha devadeva jagatpate10.15
Meaning
Indeed, You alone know Yourself by Your own internal potency, O Supreme Person, Creator of all beings, Lord of all beings, God of gods, Master of the universe.
हे पुरुषोत्तम! हे भूतभावन! हे भूतेश! हे देवों के देव! हे जगत् के स्वामी! आप स्वयं ही अपने आप को जानते हैं।
This is verse 15 of 42 in Chapter 10 (Vibhooti Yoga) of the Bhagavad Gita.