Rabbi appears nowhere in the Hebrew Bible, and Hillel never carried the title
Rabbis seem as old as Judaism itself, yet the title first surfaces in the first century CE. Famous early sages such as Hillel and Shammai bore no honorific before their names. The role grew out of catastrophe, as the loss of the Temple pushed leadership from priests towards scholars of oral law.
The word comes from Mishnaic Hebrew rabbi, master so-and-so, built on rav, master, and ultimately on a Semitic root meaning great. It is related to Arabic rabb, lord, and to a Syriac form. Sephardic and Yemenite communities long said ribbi, a pronunciation that competed with others in Ashkenazi lands until modern times. Rebbe is a later offshoot.
Ancient Israel was governed by kings, prophets, priests and the Great Sanhedrin, whose members claimed ordination in an unbroken line from Moses, but they were called priests or scribes, like Ezra. After both Temples were destroyed, the monarchy ended and the Bar Kokhba revolt failed, authority passed to the sages who began setting out the Oral Torah, later codified in the Mishnah and Talmud. The earliest bearers of the title rabban were patriarchs such as Gamaliel the Elder and Yohanan ben Zakkai. Tradition holds that rabbi was first used after 70 CE for Yohanan's students, though some evidence suggests it was already an informal courtesy earlier. The New Testament uses it for Jesus as well as for scribes and Pharisees.
Rank mattered. Sages ordained in the Land of Israel were called rabbi, while Babylonian teachers, who could not be ordained abroad, were called rav. Sherira Gaon ranked the titles: rabban above rabbi, rabbi above rav, and a bare name above them all. Some modern scholars think rabbi and rav are simply dialect variants. When Theodosius II abolished the patriarchate and Sanhedrin in 425, formal ordination in the old sense ended.
Today a rabbi is ordained by another rabbi, a process called semikhah, after studying texts from the Tanakh to the Talmud and later commentaries. Denominations set different standards. In 19th-century Germany and America, sermons, pastoral care and representing the community to outsiders grew in importance, partly modelled on the Protestant minister and giving rise to the pulpit rabbi.
Source: Rabbi
