BṚHADĀRAṆYAKA UPANISHAD · 4.3.12

प्राणेन रक्षन्न् अवरं कुलायं बहिष्कुलायाद् अमृतश् चरित्वा ।
स ईयते ऽमृतो यत्रकामं हिरण्मयः पुरुष एकहंसः ॥

prāṇena rakṣann avaraṃ kulāyaṃ bahiṣkulāyād amṛtaś caritvā ।
sa īyate ’mṛto yatrakāmaṃ hiraṇmayaḥ puruṣa ekahaṃsaḥ ॥

'Guarding with the breath (prâna, life) the lower nest, the immortal moves away from the nest; that immortal one goes wherever he likes, the golden person, the lonely bird. (2)

F. Max Müller · The Upanishads, Sacred Books of the East 15 (1884)