Brihadaranyaka Upanishad 2.4.6

ब्रह्म तं परादाद्यो2न्यत्रात्मनो ब्रह्म वेद क्षत्रं तं परादाद्यो2न्यत्रात्मनः क्षत्रं वेद लोकास्तं परादुर्योन्यत्रात्मनो लोकान्वेद देवास्तं परादुर्यो2न्यत्रात्मनो देवान्वेद भूतानि तं परादुर्यो2न्यत्रात्मनो भूतानि वेद सर्वं तं परादाद्योन्यत्रात्मनः सर्वं वेद इदं ब्रह्म इदं क्ष्त्रम् इमे लोकाः इमे देवाः इमानि भूतानि इदं सर्वं यदयमात्मा ॥

(Brihadaranyaka Upanishad 2.4.6)

The brahmana rejects one who knows him as different from the Atman. The kshatriya rejects one who knows him as different from the Atman. The worlds reject one who knows them as different from the Atman. The gods reject one who knows them as different from the Atman. Beings reject one who knows them as different from the Atman. All rejects one who knows all as different from the Atman. This brahmana, this kshatriya, these worlds, these gods, these beings, and this All are the Atman.