भासा स्वेन ज्योतिषा प्रस्वपित्यत्रायं पु-रुषः स्वयं ज्योतिर्भवति ॥ ९ ॥
In plain words
'By his own shining, by a light that belongs to him alone, he sleeps' -- and here is the point: this person himself turns out to be that very light.
Close to the Sanskrit
'By radiance, by his own light, he sleeps' -- here, this person himself becomes light.