BṚHADĀRAṆYAKA UPANISHAD · 4.3.29

यद् वै तन् न स्पृशति स्पृशन् वै तन् न स्पृशति ।
न हि स्प्रष्टुः स्पृष्टेर् विपरिलोपो विद्यते ऽविनाशित्वात् ।
न तु तद् द्वितीयम् अस्ति ततो ऽन्यद् विभक्तं यत् स्पृशेत् ॥

yad vai tan na spṛśati spṛśan vai tan na spṛśati ।
na hi spraṣṭuḥ spṛṣṭer viparilopo vidyate ’vināśitvāt ।
na tu tad dvitīyam asti tato ’nyad vibhaktaṃ yat spṛśet ॥

'And when (it is said that) there (in the Sushupti) he does not touch, yet he is touching, though he does not touch. For touching is inseparable from the toucher, because it cannot perish. But there is then no second, nothing else different from him that he could think.

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