Śvetāśvatara Upaniṣad · 6..3

तद् वै तत् सत्यं सत्यं वै तत् सत्यस्य सत्यं तद् वै तत् सत्यं सत्यं वै तत्

tad vai tat satyaṃ satyaṃ vai tat satyasya satyaṃ tad vai tat satyaṃ satyaṃ vai tat

That in truth is the Truth. The Truth in truth is That. The Truth of truth —that in truth is the Truth. The Truth in truth is That.

A spiral of affirmations about satya (truth/reality). Tat (That) is satya, and satya is tat —absolute identity. “The Truth of truth” (satyasya satyaṃ) points to a Reality that is the source of all relative truth. In our yoga practice, this is the culmination of discrimination: we do not seek partial truths but the Truth that makes all truth possible. This is the satya that does not depend on circumstances, that does not change with time, that is the immutable basis of everything mutable.