Bhagavad Gita · Purushottama YogaChapter 15, Shloka 7 (15.7)

Shankaracharya — a part "as it were". mamaiva paramātmanaḥ nārāyaṇasya aṃśaḥ bhāgaḥ avayavaḥ ekadeśaḥ iti anarthāntaram — part, portion, a single region — all one meaning; the analogy: yathā jalasūryakaḥ sūryāṃśaḥ jalanimittāpāye sūryam eva gatvā na nivartate — like the sun's reflection in water, which, when the water is removed, merges into the sun itself; yathā ghaṭādyupādhiparicchinno ghaṭādyākāśaḥ ākāśāṃśaḥ — like the space in a pot, a part of space.

Acharya Ramanuja — a real part. sanātano mama aṃśa eva san kaścid anādikarmarūpāvidyāveṣṭanatirohitasvarūpo jīvabhūto — while being my eternal part, the jiva is covered by beginningless ignorance in the form of karma; kaścit ca … asyā avidyāyāḥ … — and some (the liberated) are freed from this ignorance.

Shridhara Swami. He raises a doubt: in deep sleep and in dissolution (pralaya) all merge into the Lord — then who is it that remains in worldly existence? The answer: mamaivāṃśo yo 'yam avidyayā jīvabhūtaḥ — my part, which through ignorance has become the jiva; after sleep, punar jīvaloke … ākarṣati — it draws the senses back again.

Madhusudana Saraswati. The same question through reasoning: sarve kṣayāntā nicayāḥ patanāntāḥ samucchrayāḥ, saṃyogā viprayogāntā maraṇāntaṃ hi jīvitam — every accumulation ends in decay, every rise ends in a fall, every union ends in separation, life ends in death — then how can there be "no return"? The answer lies in the difference between attaining the Self and attaining anything else.