The notions of singular leadership and the place of the zaddik in Jewish cosmology are traced from first century rabbinic sources down to rival Hasidic claims in the mid-nineteenth century. The problem with the image of the zaddik in rabbinic literature is that the term is so widely and loosely used that it makes very difficult to assign a specific meaning to it. However the scholars delineate two general strands: First, zaddik is used in the literal sense of the term: “righteous”. The world is divided between zaddikim and reshaim, those found righteous and those found wicked by the standards of heavenly judgment. This sort of righteousness is acquired by proper behavior, especially by conquest of the passions. The second usage of the term takes the zaddik to be a unique individual, a wonder man from birth as embodied in Moses and Elijah. The zaddik as axis mundi is also the channel of interpretive power through which Israel has access to the Torah. This soul is in effect the oral Torah for its time, the bearer of the ongoing Mosaic revelation. The Talmud says that at least 36 Zaddikim Nistarim—anonymous zaddikim—are living among us in all times; they are anonymous, and it is for their sake alone that the world is not destroyed.Tzadik – Short film by Oriel Berkovits
The term zaddik will find a new evolution through the early rabbinic materials and the speculative universe of thirteenth-century Kabbalah, particularly manifest in the Zohar. Here zaddik will become a conventional term for the ninth of the ten divine emanations (sefirot). This ninth level of divinity is otherwise commonly referred to as yesod (“foundation”). This usage picked up by the early Kabbalah and much emphasized in the Zohar, will pass on into Hasidism, where the terminology of the Zohar as well as that of the early rabbis will become essential in the formulation of the new ideal type of zaddik. The Kabbalah offer also various ideas about the nature and role of the 36 Zaddikim Nistarim.
We find a further development of the zaddik motif in eastern European Hasidism, where it was to receive its fullest and most radical treatment. As Hasidism penetrated all corners of Eastern Europe and split into numerous subdivisions, it grew into a popular movement where each group was headed by a zaddik who represented a new type of religious leadership. As popularly conceived, it is through this zaddik that the devotee must turn to God. The zaddik, being at once bound to both heaven and earth, becomes a channel through which others may ascend to God and by means of which blessing comes down into the world. One couldn’t be just a “Hasid,” with no further affiliation; one had to be associated with a specific zaddik or Hasidic court. As a result, the zaddik, his family, and the attendant court establishment became a major focus of identification and social cohesion. They enjoyed a status, prestige, and authority different from those of the rabbis or elders who had been the traditional leaders of the community. The zaddik was not formally appointed or elected to his post; nor was he expected to prove his mettle in Torah scholarship. He was accepted as leader by his followers (including those not living in his own community) by virtue of his charismatic personality or spiritual eminence, and, from the nineteenth century on, by dint of his descent from a dynasty of previous zaddikim. The leadership of the dynastic zaddik is still the salient characteristic of all Hasidic groups and communities with the exception of Bratslav Hasidism.
The concept of zaddik ha-dor was very important for Rabbi Nahman of Bratslav, the great-grandson of the Besht, and it became a major motif in Nahman’s writings. It is considered that is in large part through his often unacknowledged influence that the term came to be present in other latter-day Hasidic parlance as well. Hasidism, adhere to the belief that there is a person born each generation with the potential to become Messiah, if the Jewish people warrant his coming; this candidate is known as the Zaddik Ha-Dor, meaning zaddik of the Generation. The importance and scope that this belief can reach in future days is still today an intriguing incognito.
 The monograph of Rudolph Mach on the subject is considered the best guide because it offers both an exhaustive collection and a perceptive analysis of the materials. Mach, Rudolph 1957 Der Zaddik in Talmud und Midrasch. Leiden: Brill.
 This function of the zaddik as axis mundi, the sustainer of the world, is attested by a great number of rabbinic dicta: “The entire world is sustained by the merits of the zaddikim” (Ber. 17b). “God saw that the zaddikim were few; He rose up and planted them in each generation” (Yoma 38b). “As long as there are zaddikim in the world, there is blessing in the world; when the zaddikim die, blessings vanish” (Sifre Deut 38). The tanna R. Eleazar and the amora R. Yohanan proclaim that the world was created, or is sustained, for the sake of a single zaddiq (Yoma 38b).
 Sanhedrin 97b; Sukkah 45b.
 Arthur Green The Ẓaddiq as Axis Mundi in Later Judaism Journal of the American Academy of Religion, Vol. 45, No. 3 (Sep., 1977), pp. 327-347 Oxford University Press
 On the doctrine of the Hassidic thought, see Arthur Green “Typologies of Leadership and the Hasidic Zaddik”. Ada Rapoport “God and the Zaddik as the two focal points of Hasidic Worship” in Essential Papers on Hasidism and Immanuel Etkes, “The Zaddik: The Interrelationship between Religious Doctrine and Social Organization”