This is indeed That. You who make the Self, unknown, entered into darkness, hidden in the heart — when That is known, the unknown becomes known.

Profoundly enigmatic verse: knowledge transforms what is known.

Etad vai tat — this is indeed that. The identity of Ātman and Brahman, the essential identity.

Ātmānam aviditam — the unknown Self. Not ignored but unrecognized as what it is.

Tamasi praviṣṭam — entered into darkness. Covered by avidyā, ignorance.

Hṛdi saṃvṛtam — hidden in the heart. Present but unrevealed.

Yad bhavati — what you make, what you are. The Self as that which acts through all beings.

Tad viditam asaviditam bhavati — when That is known, the unknown becomes known. The apparent contradiction indicates transformation: knowing the Self is knowing that it was never unknown, that it was always present.

Knowledge does not add anything; it reveals what always was.