BṚHADĀRAṆYAKA UPANISHAD · 3.7.12

य आकाशे तिष्ठन्न् आकाशाद् अन्तरो यम् आकाशो न वेद यस्याकाशः शरीरं य आकाशम् अन्तरो यमयत्य् एष त आत्मान्तर्याम्य् अमृतः ॥

ya ākāśe tiṣṭhann ākāśād antaro yam ākāśo na veda yasyākāśaḥ śarīraṃ ya ākāśam antaro yamayaty eṣa ta ātmāntaryāmy amṛtaḥ ॥

'He who dwells in the ether (âkâsa), and within the ether, whom the ether does not know, whose body the ether is, and who pulls (rules) the ether within, he is thy Self, the puller (ruler) within, the immortal.'

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