Śivasaṃhitā 5.214

This is complete pratyāhāra: senses withdrawn from objects though the yogi physically remains among them. Not insensibility or dissociation but the active discrimination of not feeding the chain from object to sense to mind to desire. The yogi in the marketplace is like a sleeper in the marketplace: the noise is there but doesn’t reach them.

Sarva-indriyāṇi = all senses (sarva = all, indriya = organs/senses, literally «powers of Indra»), saṃyamya = having restrained/mastered (gerund of saṃyam = to completely master), viṣayebhyas = from sense objects, vicakṣaṇa = the discerning/clairvoyant (vi-cakṣ = to see clearly). Deep sleep (suṣupti) as precise analogy for pratyāhāra.

Pratyāhāra (Patañjali’s fifth aṅga) is paradoxically the most difficult to demonstrate externally and the most radical internally: the yogi appears the same as anyone else but their interior operates from a completely different space. The Śiva-saṃhitā describes it through the suṣupti analogy because in deep sleep the senses are also naturally withdrawn—the difference is that in pratyāhāra this withdrawal is completely conscious and voluntary.