Ma'aseh Merkavah seems to have had practical applications. The belief was apparently current that certain mystic expositions of the Ezekiel chapter, or the discussion of objects connected with it, would cause God to appear. When R.
Eleazar ben Arach was discoursing upon the Ma'aseh Merkavah to R.
Yohanan ben Zakkai, the latter dismounted from his donkey, saying, "It is not seemly that I sit on the ass while you are discoursing on the heavenly doctrine, and while the Divinity is among us and ministering angels accompany us." Then a fire came down from heaven and surrounded all the trees of the field, whereupon all of them together began to recite the hymn of praise. R.
Yose HaKohen and his companion had similar experiences. The belief in the appearance of God is indicated also in the popular idea that all who inquire into the mysteries of the Ma'aseh Merkavah without being duly authorized will die a sudden death. Such a divine interposition is expressly mentioned in connection with the "story of the Creation" in Sanhedrin 95b. Rab Hananiah and Rab Hoshaiah studied the
Sefer Yetzirah and the "Hilkhot Yetzirah" respectively every Sabbath evening and succeeded in creating a calf as large as a three-year-old ox. This esoteric tendency must have led often to pessimistic and nihilistic views, as is shown by the accounts of
Elisha ben Abuyah and the Mishnaic passage, "He who speaks of the things which are before, behind, above, and below, it were better he had never been born." According to a tradition handed down by Jose b. Judah, a tanna of the second half of the second century,
Yochanan ben Zakkai was the founder of the secret doctrine. In the same passage, in both Talmuds, it is said, however, that he refused to discuss it, even in the presence of a single person, although, as already stated, R.
Eleazar ben Arach discoursed on it with him and was extravagantly praised by him; two other pupils of his, R. Joshua and R. Jose ha-Kohen, also discussed it with him. According to tradition, the second one to give instruction in these matters was R. Joshua, vice-president of the Sanhedrin under R. Gamaliel. He was succeeded by R. Akiva, and the last to teach them was R. Neḥunya ben ha-Ḳanah. R. Jose the Galilean and Pappus discussed the subject with R. Akiva. The tradition, quoted above, of the four who studied the secret doctrine mentions, besides Akiva, Simeon ben Azzai, Simeon ben Zoma, and Elisha ben Abuyah. The fate of the last-named, who was driven from Judaism by his experience, is said to have given rise to restrictive measures. The study of profane books was forbidden, and an interdiction of the public discussion of these subjects was issued, only R. Ishmael objecting. In the time of R. Judah, R. Judah b. Pazzi and Bar Ḳappara delivered public discourses on these mysteries. R. Levi regarding this as inadmissible, R. Ḥiyya declared that the chapter-headings might be taught. R. Judah ha-Nasi was at this time the authority to whom, as formerly to R. Johanan, such matters were referred. In later times the interdiction against public discussions of the story of the Creation was accepted without protest, but by way of warning this saying of Resh Laḳish was added: "His eyes shall be dull who looketh on three things—the rainbow [because it resembles Ezekiel's vision], the king [because he resembles God in majesty], and the priest [because he utters the name of God]." ==Source of Doctrines==