Bhagavad Gita · Karma Sannyasa YogaChapter 5, Shloka 15 (5.15)

Shankaracharya — the all-pervading one = Ishvara, even for the devotee. Na ādatte na ca gṛhṇāti bhaktasyāpi kasyacit pāpam — the all-pervading one does not take on the sin even of a devotee, na caiva ādatte sukṛtaṃ bhaktaiḥ prayuktam — nor the merit offered by devotees. Then why do devotees perform worship, sacrifice and charity? Answer: ajñānena āvṛtaṃ jñānaṃ viveka-vijñānam — discerning knowledge is covered by ignorance; so beings fall into the delusion "karomi kārayāmi bhokṣye bhojayāmi" — "I do, I make others do, I shall enjoy, I shall make others enjoy".

Acharya Ramanuja — the all-pervading one = the self; "ādatte" = to remove. Kasyacit sva-sambandhitayā abhimatasya putrādeḥ pāpaṃ duḥkhaṃ na ādatte na apanudati — it does not remove the sorrow of those it considers its own (a son and so on); pratikūlatayā abhimatasya sukṛtaṃ sukhaṃ ca na … apanudati — nor take away the happiness of one it considers an enemy. Why? Ayaṃ vibhuḥ na kvācitkaḥ — the self is not confined to any one body, so na kasyacit sambandhī na kasyacit pratikūlaḥ — it is no one's relative and no one's enemy. Sarvam idaṃ vāsanā-kṛtam — all this "mine / not mine" is the work of vasana. Ignorance = jñāna-virodhinā pūrva-pūrva-karmaṇā … āvṛtaṃ saṃkucitam — old karma has covered knowledge and contracted it.

The difference: Shankara — the all-pervading one is Ishvara, and ignorance is a veil over discernment; Ramanuja — the all-pervading one is the self, and ignorance is the contraction of knowledge by karma.