Brahmins are the highest ranking of the four social classes articulated in the Vedic Purusha Shukta, which describes the creation of the world through the sacrifice of the primal being, Purusha. The Brahmins are created out of the being's mouth. They were designated as the exclusive priests in the Hindu world, assigned the duty of learning and preserving the sacred texts—orally passing them on from one generation to the next—and performing the sacred rituals.
In the Vedas, sacrifice is the central religious action; it was thought to maintain and sustain the universe. The Brahmins had the exclusive knowledge of the Vedas and thus were the sole sacrificial priests; they chanted the sacred hymns and performed the many sacred acts that made up the Vedic sacrifices.
There are, in fact, dozens of different sorts of religious leaders, some of whom might be compared to priests or clergy in the western religious context: these include gurus, yogins, swamis, pandits, acharyas, sadhus, rishis, and many others.
The term guru is a Sanskrit word that is typically translated simply as "teacher." A guru is a particularly learned person, typically although not exclusively a Brahmin, who passes his (or, in some cases her) knowledge to his or her students. The role of the guru is extremely important in numerous contexts in Hinduism. The guru not only teaches, but also guides; thus a guru not only knows the sacred texts and the rituals, but also knows the abilities, capabilities, and needs of his or her students.
Gurus are often revered and worshipped by their students, regarded as actual embodiments of the knowledge they impart. Indeed, gurus in India are sometimes treated as gods; they are seen as a living incarnation of a god on earth. Such famous gurus as Maharishi Mahesh Yogi or Satya Sai Baba—to name two gurus well known in the West—as well as numerous lesser known gurus are understood by their followers to be living gods, and are treated as such. Their followers come to them for darshan, a highly significant mutual "seeing" of the divine, in which the god also sees the worshipper, and they perform puja rituals to them.
Religious leadership and authority in India derive from a number of important factors. Certainly there is the issue of birth; most religious leaders in Hinduism are Brahmins. Gurus, who are usually Brahmins, attain their status through their knowledge of sacred texts and rituals, which they pass on to their students. Religious authority can also come from the actions one performs in one's life. Mahatma Gandhi, for instance, was certainly a learned man, but his religious leadership came not from his knowledge of the sacred texts, but from his actions. It was his moral example that led people to follow him.
Some figures who are regarded by their followers as living gods attain that status through particularly auspicious, even miraculous acts. Chaitanya, the 15th-century Krishna devotee, has been elevated to the status of sainthood through his intense devotion to Krishna. He has for centuries been held up as the model of bhakti, loving devotion to the god. Likewise, Ramakrishna, the 19th-century Bengali saint, is regarded by his followers as a saint because of his intense devotion and exemplary meditation, as well as the actual content of his spiritual message.