The Brahma sutra is an early exposition of the Vedanta-interpretation of the Upanishads. It is an attempt to systematise the various strands of the Upanishads which form the background of the orthodox systems of thought.
The Brahma Sutras attempt to reconcile the seemingly contradictory and diverse statements of the various Upanishads and the Bhagavad Gita, by placing each teaching in a doctrinal context. The word “sutra” means “thread”, and the Brahma sutras literally stitch together the various Vedanta teachings into a logical and self-consistent whole.
However, the Brahma Sutras are so terse that not only are they capable of being interpreted in multiple ways, but they are often incomprehensible without the aid of the various commentaries handed down in the main schools of Vedanta thought.