The Four Who Entered Pardes (Hagigah 14b)
Our Rabbis taught: Four men entered the ‘Garden’, namely, Ben ‘Azzai and Ben Zoma, Aher, and R. Akiba. R. Akiba said to them: When ye arrive at the stones of pure marble, say not, water, water! For it is said: He that speaketh falsehood shall not be established before mine eyes. Ben ‘Azzai cast a look and died. Of him Scripture says: Precious in the sight of the Lord is the death of His saints. Ben Zoma looked and became demented. Of him Scripture says: Hast thou found honey? Eat so much as is sufficient for thee, lest thou be filled therewith, and vomit it. Aher mutilated the shoots. R. Akiba departed unhurt.