CHĀNDOGYA UPANISHAD · 6.8.2

स यथा शकुनिः सूत्रेण प्रबद्धो दिशं दिशं पतित्वान्यत्रायतनम् अलब्ध्वा बन्धनम् एवोपश्रयते ।
एवम् एव खलु सोम्य तन् मनो दिशं दिशं पतित्वान्यत्रायतनम् अलब्ध्वा प्राणम् एवोपश्रयते ।
प्राणबन्धनं हि सोम्य मन इति ॥

sa yathā śakuniḥ sūtreṇa prabaddho diśaṃ diśaṃ patitvānyatrāyatanam alabdhvā bandhanam evopaśrayate ।
evam eva khalu somya tan mano diśaṃ diśaṃ patitvānyatrāyatanam alabdhvā prāṇam evopaśrayate ।
prāṇabandhanaṃ hi somya mana iti ॥

'As a bird when tied by a string flies first in every direction, and finding no rest anywhere, settles down at last on the very place where it is fastened, exactly in the same manner, my son, that mind (the gîva, or living Self in the mind, see VI, 3, 2), after flying in every direction, and finding no rest anywhere, settles down on breath; for indeed, my son, mind is fastened to breath.

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