अजमनिद्रमस्वप्नं प्रभातं भवति स्वयम् ।
सकृद्विभातो ह्येवैष धर्म धातुस्वभावतः ॥ ८१ ॥ajamanidramasvapnaṃ prabhātaṃ bhavati svayam |
sakṛdvibhāto hyevaiṣa dharma dhātusvabhāvataḥ || 81 ||81. (Reality which is) free from birth, (which is) free from sleep and dream, reveals itself by itself For, this Dharma (i.e., Ātman) is from its very nature ever–luminous.
Shankara Bhashya (commentary)
The nature of that which is realisable by the wise is again described:—It (Ātman) reveals itself by itself. It does not depend for its revelation upon any external1 light, such as the sun, etc. Self-luminosity2 is its very nature. It is ever-luminous. This is the inherent characteristic of the Dharma, known as Ātman.
Anandagiri Tika (glossary)
1 External, etc.—Ātman itself is the substratum of everything. Therefore it cannot be dependent upon anything else.
2 Self-luminosity—Ātman is called self-luminous as, in the state of deep sleep, the real nature of Ātman is revealed though all external instruments such as the sense-organs, the mind, etc., then remain inactive.
The text characterises Ātman as free from dream and sleep. Dream indicates the wrong apprehension of truth while sleep stands for its non-apprehension. The waking state is omitted as because either it is included in the dream state or it stands for the state of knowledge.