The works of Ādi Śaṅkarācārya

Svātmaprakāśikā

Verse 50

उलूकस्य यथा भानावन्धकारः प्रतीयते ।स्वप्रकाशे परानन्दे तमो मूढस्य भासते ॥ ४७ ॥

In plain words

The owl turns toward the sun and sees only darkness. In the same way, the deluded person turns toward that self-luminous supreme bliss — and darkness is all that shows itself there.

Close to the Sanskrit

Just as, for the owl, darkness is perceived in the sun, so in the self-luminous supreme bliss darkness appears for the deluded one.