KAṬHA UPANISHAD · 2.1.4

स्वप्नान्तं जागरितान्तं चोभौ येनानुपश्यति ।
महान्तं विभुमात्मानं मत्वा धीरो न शोचति ॥ ४॥

svapnāntaṃ jāgaritāntaṃ cobhau yenānupaśyati ।
mahāntaṃ vibhumātmānaṃ matvā dhīro na śocati ॥ 4॥

The calm soul having comprehended the great Lord, the omnipresent Self by whom one beholdeth both to the end of dream and to the end of waking, ceaseth from grieving.