Importance of the Self. BG 6:5-6 Revise Atman and the optative mood.

"One should uplift oneself by the Self; One should not degrade oneself;

For the Self alone is one's friend (and) the Self only (can be) an enemy of the Self. For him who has conquered himself by the Self, (the Self) is a friend. For him who hasn't, the Self remains hostile, like an enemy." 

In BG Ch 6 verses 5 and 6 we will familiarise ourselves with the optative mood (विधि लिङ्) as well as the declension of the noun ātman आत्मन्  which varies from the 'a' ending masculine nouns we are used to. (e.g Rāma bālaka, etc) Now you have the table in front of you, you can tally words from the verse easily. Note: 

This verse is one of my favourites. Don't worry if it seems complex to start with! It's actually really very simple.

BG 6:5: 

उद्धरेदात्मनात्मानं नात्मानमवसादयेत्

आत्मैव ह्यात्मनो  बन्धुरात्मैव रिपुरात्मनः

Vigraha 

उद्धरेत् आत्मना आत्मानम् न आत्मानम् अवसादयेत् 

आत्मा एव हि आत्मनः बन्धुः आत्मा एव रिपुः आत्मनः

Anvaya 

आत्मना  आत्मानम् उद्धरेत् न हि आत्मानम् अवसादयेत्

आत्मा एव हि आत्मनः बन्धुः आत्मा एव आत्मनः रिपुः

One should uplift oneself by the Self; One should not degrade oneself;

For the Self alone is one's friend (and) the Self only (can be) an enemy of the Self.

आत्मना - By the self (3rd vibhakti/instrumental, masc. sing.) 

आत्मानम् - self ko (2nd vibhakti/accusative, masc. sing)

उद्धरेत् - he should uplift/redeem/elevate himself  (विधि लिङ्/optative, 3rd person, sing.)  

न - not

हि - verily

आत्मानम् - self ko (2nd vibhakti/accusative, masc. sing) 

अवसादयेत् - he should not degrade (विधि लिङ्/optative, 3rd person, sing.) 

अवसादयेत्  from ava+sad has the sense of  going downward, can mean decline has the sense of perish by neglect. Gita Press Gorakhpur glosses the word with अधोगति - descent or going downward.

आत्मा - Atmaa (1st vibhakti/nominative masc., sing.)

एव - only 

हि (I think the 'verily' fits better here. Even anvaya has wiggle room. Tell me what you think when you read the verse peacefully later) 

आत्मनः  of the Atmaa (6th vibhakti/genitive masc., sing)

बन्धुः friend (1st vibhakti/nominative masc., sing.)

आत्मा Atmaa (1st vibhakti/nominative masc., sing.)

एव only

आत्मनः of the Atmaa (6th vibhakti/genitive masc., sing)

रिपुः enemy ((1st vibhakti/nominative masc., sing.)

The verse 6:6

बन्धुरात्मात्मनस्तस्य येनात्मैवात्मना जितः 

अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत् 

Vigraha

बन्धुः आत्मा आत्मनः तस्य येन आत्मा एव आत्मना जितः

अनात्मनः  तु शत्रुत्वे वर्तेत आत्मा एव शत्रुवत् 

Anvaya

येन आत्मा आत्मना जितः तस्य आत्मनः एव आत्मा बन्धुः

अनात्मनः  तु आत्मा शत्रुवत्   एव वर्तेत  शत्रुत्वे  

For him who has conquered himself by the Self, (the Self) is a friend. For him who hasn't, the Self remains hostile, like an enemy

येन - by whom (जिस के द्वारा 3rd vibhakti/instrumental, masc., sing., of yat) 

आत्मा - Himself/oneself

आत्मना - by the Atmaa (3rd vibhakit/instrumental., masc., sing.) 

जितः - is won (past participle of the root ji)

तस्य - His (6th vibhakti/genitive masc., sing)

आत्मनः  Of his Atmaa (6th vibhakti/genitive masc., sing)

एव - only 

आत्मा 

बन्धुः 

अनात्मनः Of his Atmaa (6th vibhakti/genitive masc., sing)  

तु - lekin, but

आत्मा 

शत्रुवत्   - like an enemy, in the manner of an enemy

एव - only 

वर्तेत  - it would exist (विधि लिङ्  आत्मनेपद optative middle voice, pl note the full 'ta' at the end which is different from the halanta 't' in the two optatives in 6:5

शत्रुत्वे  - in enmity (7th vibhakti/locative, masc. sing.)