KAṬHA UPANISHAD · 2.3.6

इन्द्रियाणां पृथग्भावमुदयास्तमयौ च यत् ।
पृथगुत्पद्यमानानां मत्वा धीरो न शोचति ॥ ६॥

indriyāṇāṃ pṛthagbhāvamudayāstamayau ca yat ।
pṛthagutpadyamānānāṃ matvā dhīro na śocati ॥ 6॥

The calm soul having comprehended the separateness of the senses and the rising of them and their setting and their separate emergence putteth from him pain and sorrow.