ŚVETĀŚVATARA UPANISHAD · 6.20

यदा चर्मवद् आकाशं वेष्टयिष्यन्ति मानवाः ।
तदा देवम् अविज्ञाय दुःखस्यान्तो भविष्यति ॥

yadā carmavad ākāśaṃ veṣṭayiṣyanti mānavāḥ ।
tadā devam avijñāya duḥkhasyānto bhaviṣyati ॥

Only when men shall roll up the sky like a hide, will there be an end of misery, unless God has first been known.

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