Bhagavad Gita · Moksha Sannyasa YogaChapter 18, Shloka 41 (18.41)

Shankaracharya. śūdrāṇām asamāsakaraṇam ekajātitve sati vedānadhikārāt — the reason (according to him) for not joining the shudras in the compound — not being entitled to the Vedas.

Acharya Ramanuja. svakīyo bhāvaḥ svabhāvaḥ brahmaṇādijanmahetubhūtaṃ prācīnaṃ karma — svabhava = past karma, the cause of birth as a brahmin and so on.

Shridhara Swami. He regards 18.41 to the end of the chapter as sarvagītārthasāraṃ — the essence of the whole Gita: svasvādhikāravihitaiḥ karmabhiḥ parameśvarārādhanāt tatprasādalabdhajñānena — worship of Ishvara through one's own duties, and knowledge through His grace. He gives two meanings of "svabhava": (1) svabhāvaḥ sāttvikādiḥ … guṇair upalakṣaṇabhūtaiḥ — a nature that is sattvic and so on, of which the gunas are the marks; (2) svabhāvaḥ pūrvajanmasaṃskāraḥ — impressions from past lives. His commentary also counts the shudras separately dvijatvābhāvena — for not being twice-born.

Madhusudana Saraswati. He connects this to chapters 14–15: if everything is made of the three gunas, where does the weapon of non-attachment come from? The answer: svasvādhikāravihitair varṇāśramadharmaiḥ paritoṣyamāṇāt parameśvarād asaṅgaśastralābhaḥ — the weapon of non-attachment comes from Ishvara, who is pleased by one's own duties (the mention of varnashrama reflects the context of his age).