Vibhūti Yoga · Verse 15
स्वयमेवात्मनात्मानं वेत्थ त्वं पुरुषोत्तम | भूतभावन भूतेश देवदेव जगत्पते
svayam evātmanātmānaṃ vettha tvaṃ puruṣottama | bhūta-bhāvana bhūteśa deva-deva jagat-pate
You Yourself, by Your own Self, know Your own Self, oh Supreme Person; source of all beings, Lord of beings, God of gods, Lord of the universe.
The Lord knows Himself by His own nature. Svayam evātmanā — by Your own Self — no external witness needed. This indicates the svayam-prakāśa (self-illumined) nature of Brahman.
Four sublime titles: Puruṣottama — Supreme Person, between the human and the divine. Bhūta-bhāvana — source/generator of all beings. Bhūteśa — Lord of all beings. Deva-deva — God of all gods. Jagat-pate — Lord of the moving and unmoving universe.