Bhagavad Geeta: Chapter 2, Verses 14-21
Arjuna realizes that he will not be free of the sorrow he feels either by acquiring wealth or by fighting the war. He wants his delusion to be destroyed and seeks a more permanent solution. He realizes that he is confused and therefore surrenders to Sri Krishna as a disciple.
When we speak of the Self, our notion is that the Self is the body and the mind. Sri Krishna explains to Arjuna that he is grieving for those who are not worthy of it. By that, he is indicating that Arjuna has a wrong notion of himself as his body and of others as their bodies, as indicated in verses 2.12 and 2.13.
Chapter 2, Verse 14
मात्रास्पर्शास्तु कौन्तेय शीतोष्णसुखदुःखदाः ।
आगमापायिनोऽनित्यास्तांस्तितिक्षस्व भारत ॥१४॥
āgamāpāyino’nityāstāṁstitikṣasva bhārata. (14)
mātrāsparśāstu kaunteya śītoṣṇasukhaduḥkhadāḥ,
O son of Kunti, the contact between the senses and the sense objects gives rise to perceptions of happiness and distress. These are non-permanent, like heat and cold, pleasure and pain, etc. O descendent of Bharat, endure them without being disturbed.
For the senses to comprehend the sense objects, the mind has to support them. From the contact of the senses with the outer world, various sensory impulses are generated, which create joy and sorrow. When it creates joy and when it creates sorrow is dependent on other factors. Mind is always changing (not only one's mind but also the others'), the joys and sorrows come and go.
Sri Krishna tells Arjuna to forbear all these changing perceptions, through the knowledge and clarity of his real nature. He is asking Arjuna not to identify with these changing thoughts and go through this roller coaster by knowing that the joy and sorrow are of the mind. They are only mental modifications of the mind just like the body goes through various stages. The wise people are in constant awareness that "This too shall pass" while going through various experiences of joy and sorrow, success and failure.
Chapter 2, Verse 15
यं हि न व्यथयन्त्येते पुरुषं पुरुषर्षभ ।
समदुःखसुखं धीरं सोऽमृतत्वाय कल्पते ॥१५॥
yaṁ hi na vyathayantyete puruṣaṁ puruṣarṣabha,
samaduḥkhasukhaṁ dhīraṁ so’mṛtatvāya kalpate. (15)
O Arjun, best amongst men, that person for whom pleasure and pain are the same and remains steady in both, becomes eligible for realizing the immortality of the Self.
When one has the equipoise within, to calmly endure both pain and pleasure, that person is fit for the Knowledge of the Self. The Self is indicated by 'Immortality', which doesn't mean just the deathlessness of the body, it means a state where one transcends the state of identifying with the individual ego (which is conditioned by body, mind, and intellect to go through various experiences leading to a rollercoaster of emotions), to attain the infinite experience of the eternal Self.
Chapter 2, Verse 16
नासतो विद्यते भावो नाभावो विद्यते सतः ।
उभयोरपि दृष्टोऽन्तस्त्वनयोस्तत्त्वदर्शिभिः ॥१६॥
nāsato vidyate bhāvo nābhāvo vidyate sataḥ,
ubhayorapi dṛṣṭo’ntastvanayostattvadarśibhiḥ. (16)
The unreal has no being; There is no non-being of the Real. The truth of both of these has been observed conclusively by the seers of the Truth, after studying the nature of both.
In Vedanta, the unreal is that which was not in the past or that which will not be in the future, but it seemingly exists in the present. The Real is that which exists in all periods: the past, the present, and the future.
In all three levels of our existence - body, mind, and intellect, constant changes are happening, and therefore these cannot be real according to the definition previously stated. To experience these changes, there must be some substratum that is changeless and real, holding all these experiences together. That which is always existing and changeless is the Self (Consciousness).
Chapter 2, Verse 17
अविनाशि तु तद्विद्धि येन सर्वमिदं ततम् ।
विनाशमव्ययस्यास्य न कश्चित्कर्तुमर्हति ॥१७॥
avināśi tu tadviddhi yena sarvamidaṁ tatam,
vināśamavyayasyāsya na kaścitkartumarhati. (17)
That which pervades all this, know it to be Indestructible. No one can cause the destruction of That - the Imperishable.
Change can only be observed concerning the changeless. The consciousness that is constant of all the changes is permanent. This world of changes cannot exist even for a moment without the changeless, and hence it is stated as Indestructible by Sri Krishna.
Chapter 2, Verse 18
अन्तवन्त इमे देहा नित्यस्योक्ताः शरीरिणः ।
अनाशिनोऽप्रमेयस्य तस्माद्युध्यस्व भारत ॥१८॥
antavanta ime dehā nityasyoktāḥ śarīriṇaḥ,
anāśino’prameyasya tasmādyudhyasva bhārata. (18)
Only the material bodies have an end; the embodied Self within is Indestructible, Incomprehensible, and Eternal. Therefore, fight, O descendent of Bharat.
All these bodies standing here can never be permanent, they will die. Self is the very subject that gives the objects (body, mind, and intellect) the ability to function, which is why the Self cannot be comprehended through them. Self is changeless, therefore by its nature is Eternal. Indestructible indicates it always exists (beginningless, endless) and cannot be destroyed.
Chapter 2, Verse 19
य एनं वेत्ति हन्तारं यश्चैनं मन्यते हतम् ।
उभौ तौ न विजानीतो नायं हन्ति न हन्यते ॥१९॥
ya enaṁ vetti hantāraṁ yaścainaṁ manyate hatam,
ubhau tau na vijānīto nāyaṁ hanti na hanyate. (19)
Neither of them is in knowledge—the one who thinks the Self can slay and the one who thinks the Self can be slain. The Self neither slays nor can it be slain.
Whoever says I killed or I am killed, both of them don’t understand the truth. When a cup or plate is destroyed, the clay remains; when a wave disappears, the ocean remains. Self is not the body, mind, or intellect, hence it can neither kill nor be killed. The infinite cannot be destroyed, and the finite cannot be permanent.
Chapter 2, Verse 20
न जायते म्रियते वा कदाचि-
न्नायं भूत्वा भविता वा न भूयः ।
अजो नित्यः शाश्वतोऽयं पुराणो-
न हन्यते हन्यमाने शरीरे ॥२०॥
na jāyate mriyate vā kadāci-
nnāyaṁ bhūtvā bhavitā vā na bhūyaḥ,
ajo nityaḥ śāśvato’yam purāṇo-
na hanyate hanyamāne śarīre. (20)
The Self is neither born nor does it ever die; nor having once existed, does it ever cease to be. The Self is Unborn, Eternal, Immortal, and Changeless. It is not destroyed when the body is destroyed.
Never was the Self not there and then it came about - that is why it’s not born and it never dies. Self is not that which is there now and not there later (dies) or which is there later but not now (birth). Self never goes thru any modifications. Self is changeless.
The Self (consciousness) is not conditioned by time, and therefore unlike the things and beings conditioned in time (changing all the time - the death of the previous condition, and the birth of the new condition is called change), Consciousness is changeless. The destiny of those that are being born and are dying, is therefore not His. All things are born in Him, stay in Him, and die in Him.
Subjective masters defined time as an interval between experiences. Experience is impossible without thoughts. The interval between thoughts is the measure of time. From the infinite consciousness, when the first thought arose - it is zero time. When the second thought arose, there were two events - first thought experience and second thought experience. Unit of time is when second thought arose and I become conscious of it. Consciousness must be existing one second before zero time. So, Self is the most ancient, eternal (sanātana), changeless, and timeless.
Chapter 2, Verse 21
वेदाविनाशिनं नित्यं य एनमजमव्ययम् ।
कथं स पुरुषः पार्थ कं घातयति हन्ति कम् ॥२१॥
vedāvināśinaṁ nityaṁ ya enamajamavyayam,
kathaṁ sa puruṣaḥ pārtha kaṁ ghātayati hanti kam. (21)
O Partha (Arjuna), how can one who knows the Self to be Imperishable, Eternal, Unborn, and Immutable kill anyone or cause anyone to kill?
He who knows that Self is birthless, deathless, changeless, how can that person kill anyone or be killed by someone. All this happens when one takes oneself to be the body and mind. Those who “Know” (who have awakened to this higher state of consciousness) this permanent changeless state as his true nature, such an individual - whom can he kill or who can kill him.