Śvetāśvatara Upaniṣad · 4..21

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.

Seventh repetition, carrying the liturgy to its climax. Seven is a complete number in many traditions —the seven cakras, the seven lokas (worlds), the seven ṛṣis. In our yoga practice, this final repetition of the description of Brahman leaves us in presence of the ineffable. The words have done their work: not to describe but to indicate, not to define but to invite direct experience. The sadbrahma is what remains when all descriptions have been transcended.