BG 2.58

One who is able to withdraw his senses from sense objects, as the tortoise draws its limbs within the shell, is firmly fixed in perfect consciousness.

2.58. When he withdraws all his sense-organs from sense-objects, just as a tortoise does all of its own limbs, then he is declared to be a man-of-stabilized-intellect.

2.58 He who can withdraw his senses from the attraction of their objects, as the tortoise draws his limbs within its shell - take it that such a one has attained Perfection.

2.58 Yada samharate etc. the nomenclature is not an expression having a composite of both the forces of etymological and traditional meanings, like the word pankaja 'a lotus'. But it has only the etymological force like the word pacaka 'a cook'. Whenever he (the sage) withdraws just in his own self-just as a tortoise keeps its limbs in its bossom-from the sense-objects i.e., warding off from the sense-objects, then and then [only] he is man-of-stabilized-intellect. Or [the passage may mean :] Whenever he withdraws, within his own Self, [all], beginning from the sense-objects upto sense-organs i.e., when he approprites in his own Self all in the form of sense-objects and sense-organs. But, how is it that the nomenclature 'a man-of-stabilized-intellect' does not hold good in the case of an ascetic ? It is answered-

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.

2.58 And besides, yada, when; ayam, this one, the sannyasin practising steadfastness in Knowledge; samharate, fully withdraws; ['Fully' suggests absolute firmness in withdrawal, and 'withdraws' suggests full control over the organs] indriyani, the senses; indriya-arthhyah, from all the objects of the senses; iva, as; kurmah, a tortoise; sarvasah, wholly (withdraws); angani, its limbs, from all sides out of fear; when the man engaged in steadfastness to Knowledge withdraws thus, then tasya, his; prajna, wisdom; pratisthita, remains established (the meaning of this portion has already been explained). As to that, [That is , so far as the phenomenal world is concerned.] the organs of a sick person, too, cease to be active when the refrains from sense-objects; they get fully withdrawn like the limbs of a tortoise. but not so the hankering for those objects. How that (hankering) gets completely withdrawn is being stated:

2.58 When one is able to draw his senses from the objects of sense on every side, as a tortoise draws in its limbs, then his wisdom is firmly set.

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.