When one completely withdraws the senses from sense objects, as a tortoise draws in its limbs, then one’s wisdom is firmly established.

The image of the tortoise (kūrma) is one of the most evocative in yogic literature. It illustrates pratyāhāra, the withdrawal of the senses — the fifth limb of Patañjali’s Aṣṭāṅga Yoga.

Saṃharate (withdraw, gather in) suggests a voluntary inward movement. The tortoise doesn’t lose its limbs; it retracts them when appropriate. Likewise, the yogī doesn’t destroy their senses but learns to direct them at will.

Prajñā pratiṣṭhitā — “wisdom firmly established” — describes the sthitaprajña, the sage of stable mind, the central theme of chapter 2. This stability is not repression but freedom: the senses no longer drag the mind.

In practice, pratyāhāra occurs naturally in deep āsana: when attention concentrates on breath and internal sensations, external noise fades.

The metaphor also suggests protection: the tortoise withdraws to preserve itself. The yogī turns inward to protect their peace.