Bhagavad Gita · Karma Sannyasa YogaChapter 5, Shloka 18 (5.18)

The list deliberately runs "from one end to the other". On one side, the most respected in society's eyes — the brahmin with learning and humility; on the other, the dog and the śvapāka — whom that society placed lowest of all. In between, the cow and the elephant. The Gita says: in the vision of the wise, this ladder disappears.

Shankaracharya — one untouched Brahman in all. Vidyā ātmano bodho vinayaḥ upaśamaḥ — learning means awareness of the self, humility means calm. Then Shankara sets out an order according to the gunas: uttama-saṃskāravati brāhmaṇe sāttvike, madhyamāyāṃ ca rājasyāṃ gavi, … atyantam eva kevala-tāmase hasty-ādau — the sattvic brahmin, the rajasic cow, the tamasic elephant and so on — sattvādi-guṇaiḥ … atyantam eva aspṛṣṭaṃ samam ekam avikriyaṃ tat brahma draṣṭuṃ śīlaṃ yeṣāṃ te paṇḍitāḥ sama-darśinaḥ — those whose nature is to see that Brahman, utterly untouched by all these gunas and impressions, the same, one and changeless, are the wise who see equally.

Shankara also raises an objection: the smriti (samāsamābhyāṃ viṣama-same pūjātaḥ, Gautama Dharmasūtra 17.20) says that in worship it is a fault to treat equals and unequals the other way round — so are those of equal vision abhojyānnāḥ (people whose food is not to be eaten), at fault? His answer (5.19): na te doṣavantaḥ — they are not at fault; that rule is dehādi-saṅghātātma-darśanābhimānavad-viṣayam — only for those who take the body to be the self; brahma tu sarva-guṇa-doṣa-saṃbandha-varjitam — Brahman is beyond all connection with merit and fault.

Acharya Ramanuja — the self in all is of the one form of knowledge. Atyanta-viṣamākāratayā pratīyamāneṣu ca ātmasu — in these selves that appear utterly unequal; paṇḍitāḥ ātma-yāthātmya-vidaḥ jñānaikākāratayā sarvatra sama-darśinaḥ — those who know the truth of the self see equally, seeing everywhere "the one form of knowledge"; viṣamākāras tu prakṛteḥ na ātmanaḥ — inequality belongs to prakriti (the body), not to the self.

The difference: Shankara — one Brahman in all; Ramanuja — many selves, but all alike (of the nature of knowledge). Both reach the same conclusion: the difference belongs to the body, not to the self.