When, like the tortoise which withdraws on all sides its limbs, he withdraws his senses from the sense-objects, then his wisdom becomes steady.
In simple words
Krishna gives Arjuna a picture: "Think of a tortoise pulling all its limbs inside its shell. When a person can pull back their senses from the things that tempt them, just like that — their wisdom becomes completely steady."
Word-by-word meanings
यदाwhenसंहरतेwithdrawsचandअयम्this (Yogi)कूर्मःtortoiseअङ्गानिlimbsइवlikeसर्वशःeverywhereइन्द्रियाणिthe sensesइन्द्रियार्थेभ्यःfrom the senseobjectsतस्यof himप्रज्ञाwisdom प्रतिष्ठिता is steadied
2.58 यदा when? संहरते withdraws? च and? अयम् this (Yogi)? कूर्मः tortoise? अङ्गानि limbs? इव like? सर्वशः everywhere? इन्द्रियाणि the senses? इन्द्रियार्थेभ्यः from the senseobjects? तस्य of him? प्रज्ञा wisdom प्रतिष्ठिता is steadied.Commentary Withdrawal of the senses is Pratyahara or abstraction. The mind has a natural,tendency to run towards external objects. The Yogi again and again withdraws the mind from the objects of the senses and fixes it on the Self. A Yogi who is endowed with the power of Pratyahara can enter into Samadhi even in a crowded place by withdrawing his senses within the twinkling of an eye. He is not disturbed by tumultuous sounds and noises of any description. Even on the battlefield he can rest in his centre? the Self? by withdrawing his senses. He who practises Pratyahara is dead to the world. He will not be affected by the outside vibrations. At any time by mere willing he can bring his senses under his perfect control. They are his obedient servants or instruments.
Contemporary scholarly and practical interpretations for modern seekers.
This interpretation draws on a specific tradition and may not represent the view of any single school. For authoritative guidance within a specific tradition, seek a qualified teacher.
Modern
# BG 2.58
After describing the self-contentment, equanimity, and non-attachment of the wise person, this verse presents the complete mastery of the senses that characterizes such a one. Through a most apt analogy, the marks of wisdom are made clear here. Just as a tortoise withdraws its limbs into itself upon sensing any danger and thereby secures itself, so too does the wise person possess the capacity to withdraw the senses from their objects at will, and equally to engage them as needed.
According to the Vedantic process of direct knowledge, the consciousness-infused modifications of the inner instrument perceive the form of external objects situated in space through the gateway of the senses, and thereby direct knowledge of those objects arises. The Katha Upanishad describes this process thus: the light of consciousness shines forth through the seven openings in the head—the two eyes, two ears, two nostrils, and the mouth—like rays of light, illuminating all objects. In this way, each particular sense illuminates its particular object: the eye perceives form and color, the ear perceives sound, and so forth.
We may draw an analogy from electricity in the material world: the same force that manifests as light in an ordinary bulb and illuminates objects can also pass through X-ray tubes, penetrate the gross body, and illuminate internal organs not ordinarily visible.
Thus each person acquires knowledge of the entire external world through the five senses of knowledge. The continuous stream of sensory impressions received through these senses gives rise to countless distractions in the mind. Without eyes, there arise no distractions from forms; a deaf person does not hear criticism of himself and thus experiences no mental disturbance—and the same principle applies to the other senses. The Lord declares that the wise person possesses the capacity to withdraw the senses from their objects at will.
In the science of yoga, this capacity for sense-withdrawal is called pratyahara, which the yogi attains through pranayama. When the devotee's heart is filled with love for the divine beauty of the Lord, the mind naturally becomes free from sensory distractions—what Vedanta calls uparati. The sincere seeker attains this through the power of discrimination, by understanding the limited and futile nature of sense-objects and recognizing the blissful nature of the Self.
A person who abstains from sense-enjoyment due to illness or other circumstance may indeed distance himself from objects, yet their taste remains. How can even this taste be transcended? Listen.