BṚHADĀRAṆYAKA UPANISHAD · 4.5.4

सा होवाच मैत्रेयी --
येनाहं नामृता स्याम् किम् अहं तेन कुर्याम् ।
यद् एव भगवान् वेद तद् एव मे ब्रूहीति ॥

sā hovāca maitreyī --
yenāhaṃ nāmṛtā syām kim ahaṃ tena kuryām ।
yad eva bhagavān veda tad eva me brūhīti ॥

And Maitreyî said: 'What should I do with that by which I do not become immortal? What my Lord knoweth (of immortality), tell that clearly to me.'

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