Brahma Sūtram — The Systematic Foundation of Vedānta
Brahma Sūtram (also: Vedānta Sūtras, Śārīraka Mīmāṃsā, Uttara Mīmāṃsā) is the foundational systematic text of all Vedānta philosophy, attributed to the sage Vedavyāsa (Bādarāyaṇa). It consists of 545 sūtras (terse aphoristic statements) organized into four adhyāyas (chapters): Samanvaya (harmonisation — establishing Brahman as the subject of all Vedāntic teaching), Avirodha (non-contradiction — answering objections to this thesis), Sādhana (means — exposition of the paths of liberation), and Phala (fruit — the nature of liberation and the liberated state). Together with the ten principal Upaniṣads and the Bhagavad Gītā, the Brahma Sūtram forms the prasthānatraya — the triple canonical foundation to which every Vedānta school must present a coherent commentary in order to establish its doctrinal authority.
The challenge of the sūtras: The Brahma Sūtras are among the most terse and elliptical texts in the Sanskrit literary tradition. Individual sūtras are frequently no more than two or three words, and their meaning is often irresolvable without commentary. This very terseness is philosophically significant: it demands a bhāṣyakāra (commentator) whose interpretation will make visible the underlying coherence of the text — and whose interpretation will therefore constitute a full philosophical system. This is why all the great Vedāntic schools (Advaita, Viśiṣṭādvaita, Dvaita, Śuddhadvaita, Acintya-bhedābheda, and others) are constituted by their commentaries on these same sūtras. The sūtras do not univocally teach any single system; their meaning is only revealed through the lens of a living interpretive tradition.
Rāmānuja's Śrī Bhāṣyam: Rāmānuja's commentary on the Brahma Sūtras — the Śrī Bhāṣyam — is the constitutive text of Viśiṣṭādvaita. In it, Rāmānuja: (i) establishes that Brahman is Nārāyaṇa with Śrī, the personal God of the Upaniṣads; (ii) systematically refutes Śaṅkara's Advaita and the dualistic interpretations; (iii) expounds the śarīra-śarīrī relationship (cit and acit as the body of Brahman); (iv) explains the paths of bhakti and prapatti as legitimate upāyas for liberation; and (v) describes the liberated state as eternal kaiṅkarya in Śrīvaikuṇṭha. The Śrī Bhāṣyam is remarkable not only for its philosophical rigour — the extended pūrva-pakṣa (opponent's view) sections are among the most lucid expositions of Advaita in the tradition — but for the devotional warmth that pervades even its most technical passages.
Yāmunāchārya and Rāmānuja's labour: The story of how the Śrī Bhāṣyam came to be composed is itself theologically charged. Yāmunāchārya (Alavandar) is said to have held three fingers bent at the time of his attaining Paramapadam — indicating three tasks he had not accomplished in this world. One was: to write a commentary on the Brahma Sūtras. When Rāmānuja arrived too late to receive Yāmunāchārya's direct instruction, he vowed to fulfil his teacher's uncompleted work. The Śrī Bhāṣyam, composed after years of study at Śrī Śaradā Pīṭha in Kāśmīr and at Śrīraṅgam, is the fulfilment of that vow — a labour of love offered at the feet of both Bhagavān and the Āchārya.