776
Śrīmad-Bhāgavatam
[ Canto 4, Ch. 20 ]
material body is called  deha , or the embodiment of the soul. The body is changing at every moment, but the soul is fixed; therefore the soul is called  kūṭastham . The change of body is enacted by the reactions of the three modes of nature. One who has understood the fixed position of the soul should not be disturbed by the incoming and outgoing interactions of the modes of material nature in the form of happiness and distress. In  Bhagavad-gītā  also Lord Kṛṣṇa recommends that since happiness and distress come and go due to the interaction of the modes of nature on the body, one should not be disturbed by such external movements. Even though one is sometimes absorbed in such external movements, he has to learn to tolerate them. The living entity should be always indifferent to the action and reaction of the external body.
Lord Kṛṣṇa says in  Bhagavad-gītā  that the body made of the gross physical elements (earth, water, fire, air and sky) and the subtle elements (mind, intelligence and ego) is completely different from the soul proper. One should therefore not be disturbed by the action and reaction of these eight gross and subtle material elements. The practical process to attain this stage of indifference is to execute devotional service. Only one who constantly engages in devotional service twenty-four hours a day can be indifferent to the action and reaction of the external body. When a man is absorbed in a particular thought, he does not hear or see any external activities, even though they are enacted in his presence. Similarly, those who are fully absorbed in devotional service do not care what is going on with the external body. That status is called  samādhi . One who is actually situated in  samādhi  is understood to be a first-class  yogī .
TEXT 12
मिन्नस्य लिङ्गस्य गुणप्रवाहो द्रव्यक्रियाकारकचेतनात्मनः । दृष्टासु सम्पत्सु विपत्सु क्षरयो न विक्रियन्ते मयि बद्धसौहृदाः ॥१२॥
bhinnasya liṅgasya guṇa-pravāho dravya-kriyā-kāraka-cetanātmanaḥ dṛṣṭāsu sampatsu vipatsu sūrayo na vikriyante mayi baddha-sauhṛdāḥ