यदा संहरते चायं कूर्मोऽङ्गानीव सर्वशः।
इन्द्रियाणीन्द्रियार्थेभ्यस्तस्य प्रज्ञा प्रतिष्ठिता।।2.58।।
2.58 And when this one fully withdraws the senses from the objects of the senses, as a tortoise wholly (withdraws) the limbs, then his wisdom remains established.
2.58 When one is able to draw the senses away from the sense-objects on every side when the senses try to contact the sense-objects, just as a tortoise draws in its limbs, and is capable of fixing his mind on the self - he too is of firm wisdom. Thus there are four stages of devotion to knowledge, each stage being perfected through the succeeding stage. Now Sri Krsna speaks of the difficulty of the attainment of firm devotion to knowledge and the means of that attainment.
Yadaa samharate chaayam kurmo’ngaaneeva sarvashah; Indriyaaneendriyaarthebhyas tasya prajnaa pratishthitaa.
yadā—when; sanharate—withdraw; cha—and; ayam—this; kūrmaḥ—tortoise; aṅgāni—limbs; iva—as; sarvaśhaḥ—fully; indriyāṇi—senses; indriya-arthebhyaḥ—from the sense objects; tasya—his; prajñā—divine wisdom; pratiṣhṭhitā—fixed in