Śvetāśvatara Upaniṣad · 4..13

तदेतद्ब्रह्मापूर्वमपरमनन्तं बाह्यं व्याप्यं नित्यं विभुं सूक्ष्मं सन्मात्रं सद्ब्रह्म

tadetadbrahmāpūrvamaparamanantaṃ bāhyaṃ vyāpyaṃ nityaṃ vibhuṃ sūkṣmaṃ sanmātraṃ sadbrahma

That is this Brahman, without before or after, infinite, external, omnipenetrating, eternal, omnipresent, subtle, essence of being, true Brahman.

Third repetition of this description, forming a triple pattern with verses 10 and 12. In tradition, three is stability, completeness. In our yoga practice, this triple repetition invites deep contemplation: what does it mean that Brahman is apūrva (without precedent)? What does it imply that it is vyāpya (omnipenetrating)? Each word is a mantra, a vibration that, when meditated upon, reveals its meaning not as concept but as existential truth. The sadbrahma is not an object of faith but the reality of our own being.