Śivasaṃhitā 5.216

This verse directly quotes the Taittirīya Upaniṣad (II.9.1)—one of Vedanta’s most solemn statements about Brahman’s ineffability. That a haṭhayoga text incorporates this Upaniṣadic quote reveals its philosophical depth: bodily techniques and Vedantic gnosis are not separate systems but convergent approximations toward the same reality.

Yatas = from where, vāco = speech (vāc), nivartante = return (ni-vṛt = to turn back), aprāpya = without having reached (a = without, prāpya = having reached), manasā saha = together with mind. The described linguistic impossibility is not a failure but a sign of pointing correctly.

The fact that this Taittirīya quote appears twice in Śiva-saṃhitā chapter 5 (verses 180 and 216) underlines its function as theological keel: it is the constant north to which all practices point. The text says implicitly: all the techniques described—āsana, prāṇāyāma, mudrā, cakra, mantra—point toward that which no technique can capture but all can prepare.