B.G 6.05 and 06

उद्धरेदात्मनाऽत्मानं नात्मानमवसादयेत्। आत्मैव ह्यात्मनो बन्धुरात्मैव रिपुरात्मनः ॥५॥

uddharedātmanā'tmānaṁ nātmānamavasādayet। ātmaiva hyātmano bandhurātmaiva ripurātmanaḥ ॥5॥

One should uplift himself with the help of mind and should not degrade. Certainly, the mind alone is the friend of oneself, and also the enemy.

बन्धुरात्माऽत्मनस्तस्य येनात्मैवाऽत्मना जितः। अनात्मनस्तु शत्रुत्वे वर्तेताऽत्मैव शत्रुवत् ॥६॥

bandhurātmā'tmanastasya yenātmaivā'tmanā jitaḥ। anātmanastu śatrutve vartetā'tmaiva śatruvat ॥6॥

The mind becomes the friend of oneself, by whom indeed the mind is conquered with the help of the lord. But the unconquered mind turns hostile. Indeed, such a mind acts like an enemy.

Gīta Tātparya 6.05 and 06

As there are testimonials to say one must uplift oneself with the help of the supreme being, the word 'atma' could refer to 'paramatma', the supreme being, as well. This aligns well with the next verse, which states 'paramātmā samāhitaḥ' , i.e. 'he is stationed with equanimity in the supreme personality'.

"Indeed, one should uplift the individual soul from the cycle of birth and death with the help of the Supreme Lord. Lord Vishnu is the eternal friend of the virtuous, and indeed, the Supreme personality is the eternal enemy of the non-virtuous. Conquered by devotion, through His grace, He comes under control and remains a friend. To others, He behaves like an enemy."

- such testimonials as well.

The next sentence concludes by stating 'paramātmā samāhitaḥ' (Gita 6.7), i.e. 'he is stationed with equanimity in the supreme personality'. (Thus 'atma' can refer to 'paramatma' as well.)