Katha Upanishad Verse 2.3.5

The clarity with which the Atman is perceived varies by realm. In the human self, it can be seen clearly as in a mirror. In other worlds, it is as indistinct as a dream or reflections in water. Only in the supreme spiritual state (Brahma-loka) is the distinction as clear as light and shade.

Sanskrit Verse

यथादर्शे तथात्मनि यथा स्वप्ने तथा पितृलोके ।
यथाप्सु परीव ददृशे तथा गन्धर्वलोके छायातपयोरिव ब्रह्मलोके ॥ ५ ॥

Transliteration

yathādarśe tathātmani yathā svapne tathā pitṛloke |
yathāpsu parīva dadṛśe tathā gandharvaloke chāyātapayoriva brahmaloke || 5 ||

Translation

As in a mirror, so within one’s self; as in dreams, so in the world of the manes; as indistinctly seen in water, so in the world of the Gandharvas; as of light and shade, so in the world of Brahma.