अतद्व्यावृत्तिरूपेण वेदान्तैर्लक्ष्यतेऽद्वयम् ।अखण्डानन्दमेकं यत्तद्ब्रह्मेत्यवधारयेत् ॥ ५७ ॥
In plain words
The Upaniṣads point to the non-dual by clearing away everything it is not. What is left is one, undivided, bliss without a seam — settle it firmly: that is Brahman.
Close to the Sanskrit
By way of the exclusion of what is not-That, the non-dual is indicated by the Upaniṣads; that which is undivided bliss, one — that one should ascertain as 'Brahman'.