CHĀNDOGYA UPANISHAD · 8.7.1

य आत्मा अपहतपाप्मा विजरो विमृत्युर् विशोको विजिघत्सो ऽपिपासः सत्यकामः सत्यसंकल्पः सो ऽन्वेष्टव्यः स विजिज्ञासितव्यः ।
स सर्वांश् च लोकान् आप्नोति सर्वांश् च कामान् यस् तम् आत्मानम् अनुविद्य विजानातीति ह प्रजापतिर् उवाच ॥

ya ātmā apahatapāpmā vijaro vimṛtyur viśoko vijighatso ’pipāsaḥ satyakāmaḥ satyasaṃkalpaḥ so ’nveṣṭavyaḥ sa vijijñāsitavyaḥ ।
sa sarvāṃś ca lokān āpnoti sarvāṃś ca kāmān yas tam ātmānam anuvidya vijānātīti ha prajāpatir uvāca ॥

Pragâpati said: 'The Self which is free from sin, free from old age, from death and grief, from hunger and thirst, which desires nothing but what it ought to desire, and imagines nothing but what it ought to imagine, that it is which we must search out, that it is which we must try to understand. He who has searched out that Self and understands it, obtains all worlds and all desires.'

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