CHĀNDOGYA UPANISHAD · 8.3.4

अथ य एष संप्रसादो ऽस्माच् छरीरात् समुत्थाय परं ज्योतिर् उपसंपद्य  स्वेन रूपेनाभिनिष्पद्यत एष आत्मेति होवाच ।
एतद् अमृतम् अभयम् एतद् ब्रह्मेति ।
तस्य ह वा एतस्य ब्रह्मणो नाम सत्यम् इति ॥

atha ya eṣa saṃprasādo ’smāc charīrāt samutthāya paraṃ jyotir upasaṃpadya  svena rūpenābhiniṣpadyata eṣa ātmeti hovāca ।
etad amṛtam abhayam etad brahmeti ।
tasya ha vā etasya brahmaṇo nāma satyam iti ॥

'Now that serene being which, after having risen from out this earthly body, and having reached the highest light (self-knowledge), appears in its true form, that is the Self,' thus he spoke (when asked by his pupils). This is the immortal, the fearless, this is Brahman. And of that Brahman the name is the True, Satyam,

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)