Srimad BhagavadGita

In the previous śloka the reward of practising jñāna yoga was described, which is that instead of indulging in sense gratification one has a constant vision of the soul. Its prior state is discussed in this śloka, where the reward at this particular stage of jñāna yoga is that the sight of sense objects does not cause any changes in him. 

Kṛṣṇa says to Arjuna, “Just as the waters of the rivers enter the ocean which is always full by itself and steady, in the same manner the sense objects enter into one who has control over his senses. He alone attains peace and not someone who hankers after sense objects.”

yadvat āpaḥ praviśanti (As the waters of the rivers enter) These words convey the meaning that ‘As the water in the ocean remains full and unchanged whether it rains incessantly or not, whether more water flows through rivers or less...

apūryamāṇam samudram (The ocean which is full by itself) Here, it must be understood that the ocean which is always full of water is given as an illustration for a jñāni who without getting affected by the sense objects, derives contentment from the vision of the soul alone. He is fulfilled in himself. It is not correct to interpret these words as, ‘The ocean which is full due to the pouring of the waters of the rivers into it’.

acala pratiṣṭhaṃ (The ocean remains unchanged, irrespective of the flow of the river water) The ocean is not like the river which overflows its banks into the surrounding areas during the rainy season and dries up during the summers.  

tadvat sarve kāmāḥ yaṃ praviśanti (Similarly the sense objects enter this person whose senses are in his control)

tadvat (Similarly) 

sarve kāmāḥ (All the sense objects like sounds, forms, etc) kāmyante iti kāmāḥ, based on this derivation

for kāmāḥ and the present context, it is apt to interpret the meaning as 'All the desirable sense objects'.

yaṃ praviśanti (Enter into the person who has achieved control over his senses) Since the illustration

about the ocean highlights its speciality that its waters remain full and unchanged, the person

referred to by the word 'yaṃ' is one who just like the ocean, does not experience any changes. He is none

other than the jñāna yoga practitioner described earlier who has control over his senses. Since the sense

objects do not enter into the body like food and water, 'all the sense objects which enter into the person’

would mean ‘all the sense objects which become objects for his various senses'. Through the respective

senses they become the objects of his knowing (jñāna). The meaning therefore is that, just as the

ocean remains full and unchanged irrespective of the water from rivers entering it, similarly jñāna yogi does

not undergo any changes whether the trivial sense objects like sounds, forms, smells, tastes and textures

become the objects for his senses or not. This is achieved on account of his contentment derived from his

vision of the soul. 

sa śāntim āpnoti (He alone experiences the peace of becoming free from the experience of sense objects) This means that one who is immersed in the joyful experience of the eternal and pure (free from defects) soul will not desire for unsteady, grief mixed, trivial drizzles of happiness resulting from the experience of sense objects. This same meaning is derived in another way with the words 'na kāmakāmī'.

na kāmakāmī (One who hankers after kāmas (desire for the sense objects) and as a result experiences changes (distortion in nature) in himself can never experience the above mentioned peace of becoming free from the experience of sense objects). As per the derivation kāmān kāmayatum śīlaṃ yasya saḥ kāmakāmī, the word kāmakāmī refers to 'one who has the tendency to desire for the sense objects'. However, since the topic under discussion in the śloka is the changes experienced, it is apt to understand kāmakāmī to be one who undergoes changes in himself as a result of his desire for the sense objects. One who is subject to such changes in himself due to his desire for sense objects, cannot become free from the craving for those objects until the desires get removed. The mere sight of the objects will cause changes in him. Even when the objects are not in sight, he can escape neither the desire nor the changes caused by them.