The teachings of the Buddha are distinguished by his initiatives towards unprecedented social changes. The Indian society of the Buddha's day, was uncompromising in its attitude towards caste-division.
The hide-bound conservatism at that age, reduced some sections of society to a demeaning and utterly degrading level. In a daring challenge to the strongly entrenched views of his day, the Supreme Buddha upheld the nobility of the human person. This was two-thousand, five-hundred years ago - long centuries before modern thinkers evolved philosophies to safeguard human rights.
The Buddha's concern for those who are down-trodden, harshly exploited and ostracized for no fault of theirs, set him apart as the greatest humanist the world has ever known. In a social context in which the domination of the brahmins who claimed unquestioned superiority because of the reason of birth, the Buddha wrought a revolution of ideas, that echoes down the corridors of time, even to our day. The formula of the Buddha's thought revolution is contained in many of his discourses. But it is Vasala Sutta ( The Discourse on outcastes ) that the Buddha's challenging views are unambiguoursly articulated. Vasala Sutta ( The Discourse on outcastes ) derives from the Buddha's response to a caste-proud Brahmin, who insulted the Buddha, for daring to appear at the site of a fire-ritual he was getting ready to perform.