The apāna withdraws from the prāṇa, together with the senses and mind, all together. The tejas (light) of knowledge, the vṛṣaṇa (vigorous bull), carries the light of Brahman that enters here.

This verse describes the process of prāṇāyāma and the withdrawal of the senses toward the inner center. The apāna (downward-moving wind) unites with prāṇa (upward-moving wind), and with them withdraw the indriyas and manas. The tejas (luminous energy) of prajñāna (supreme knowledge) is like a vṛṣaṇa (powerful bull) that carries the light of Brahman to manifestation. It is a technical description of the state of samādhi where all energies concentrate at the central point.