Sādhana Pāda · Sutra 54
स्वविषयासंप्रयोगे चित्तस्वरूपानुकार इवेन्द्रियाणां प्रत्याहारः
svaviṣayāsaṃprayoge cittasvarūpānukāra ivendriyāṇāṃ pratyāhāraḥ
Pratyāhāra is when the senses withdraw from their objects and adopt, as it were, the nature of the mind.
Pratyāhāra is the interiorization of the senses. Normally, the indriyas (senses) are directed outward, toward their proper objects (svaviṣaya).
In pratyāhāra, the senses disconnect (asaṃprayoga) from external objects and follow (anukāra) the mind inward.
It’s like turtles retracting their limbs: the senses are gathered within.
Iva (“as it were”) indicates that the senses don’t become mind, but adopt its inward direction.
This is the bridge between external and internal practices. Without pratyāhāra, every sound, every sensation, interrupts meditation.