The Schocken Book of Jewish Mystical Testimonies : A Unique and Inspiring Collection of Accounts by People Who Have Encountered God, from Biblical Times to the Present Paperback - 1997

From Chapter 2: "The Four Who Entered the King's Orchard"

The Four Who Entered the King's Orchard
This famous passage in the Babylonian Talmud . . . has been discussed at length through the centuries as the main statement in rabbinic literature of mystical experience . . . The four sages mentioned all flourished in the first half of the second century . . . As to the object of this mystical contemplation, it is in all probability the Chariot of Ezekiel.

TEXT
Our Rabbis taught: Four entered an orchard and these are they: Ben Azzai, Ben Zoma, Aher and Rabbi Akiva. Rabbi Akiva said to them: "When you reach the stones of pure marble, do not say: 'Water, water!' For it is said: 'He that speaketh falsehood shall not be established before mine eyes' [Ps. 101:7]." Ben Azzai gazed and died. Of him Scripture says: "Precious in the sight of the Lord is the death of His saints" [Ps. 116:15]. Ben Zoma gazed and was stricken. Of him Scripture says: "Hast thou found honey? Eat as much as is sufficient for thee, lest thou be filled therewith, and vomit it" [Prov. 25:16]. Aher cut down the shoots. Rabbi Akiva departed in peace.

COMMENTS
Ben Azzai and Ben Zoma were both named Simeon. They were never ordained as rabbis and it has been suggested that this is why they are not referred to as "Simeon ben Azzai" and "Simeon ben Zoma," it being considered insulting to them to refer to them by their full name without the title. Aher is Elisha ben Avuyah. "Aher" means "the other one," a name given to him when he became an apostate, according to the implications of our passage, as a result of his vision. Based on this passage the term "cutting down the shoots" is used in later Jewish literature as a synonym for "heresy." In the passage, it is implied that the mystical ascent of the soul is fraught with danger both to body and soul. Only Rabbi Akiva emerges unscathed. Rashi's comment to the passage deserves to be quoted in full as evidence of how this matter was viewed in the traditions of 11th-century France. Rashi comments as follows:

Pure marble: shining like clear water.

Do not say: Water, water! is here, how can we go on further?

Gazed: toward the Shekhinah.

Precious in the sight of the Lord is the death of His saints: His death was hard for God since he was still a young man, yet he had to die because it is said: "For man shall not see Me and live" (Exodus 33:20).

Was stricken: He became demented.