अहमेकोऽपि सूक्ष्मश्च ज्ञाता साक्षी सदव्ययः ।तदहं नात्र सन्देहो विचारः सोऽयमीदृशः ॥ १६ ॥
In plain words
I am one, and subtle. I am the knower, the witness, real, and beyond all wearing away. That is what I am — and about this there is no doubt left. This is what inquiry looks like: exactly this.
Close to the Sanskrit
I am one, and subtle, the knower, the witness, existent and imperishable. That am I — here there is no doubt. This inquiry, that very one, is of just this kind.