Śvetāśvatara Upaniṣad · 4..16
तदेतदक्षरं ब्रह्म तदेतदक्षरं परमं तद्ब्रह्म तद्परं तद्ब्रह्म तद्विद्वान् ब्रह्मा भवति निरात्मा निराकाङ्क्षः सोऽश्नुते सार्वभौमान् सुखान् स एवं वित्तः
tadetadakṣaraṃ brahma tadetadakṣaraṃ paramaṃ tadbrahma tadparaṃ tadbrahma tadvidvān brahmā bhavati nirātmā nirākāṅkṣaḥ so'śnute sārvabhaumān sukhān sa evaṃ vittaḥ
That is this immortal Brahman, that is this supreme Brahman. That Brahman, that supreme Brahman —knowing That, one becomes Brahman, without ego, without desires, enjoys universal joys, thus known.
Fourth repetition of this verse, completing the extended pattern. The promised transformation —brahmā bhavati— is certain for whoever knows genuinely. In our yoga practice, this is the guarantee: there is no risk of failure if knowledge is authentic. The sārvabhaumān sukhān (universal joys) are not a reward granted but the very nature of the Brahman that we are. Ego and desires are like clouds obscuring the sun; when they dissipate, the light has always been there.