A min — a heretic, an opponent of the Rabbis' tradition — came to Rabbi Yishmael with a stack of strange dreams he wanted interpreted. He had clearly hoped that the Rabbi would play the role of professional dream reader, offering mystical meanings and perhaps embarrassing himself by guessing wrong.
Rabbi Yishmael listened to each dream in turn. Then he interpreted them all — every single one — as pointing directly to a particular sexual sin the heretic had been committing in secret.
The min was stunned. The dreams, on their surface, were about rivers and animals and wandering through unfamiliar houses. Rabbi Yishmael had heard them as something else. The Talmud (Berakhot 55b–56b) preserves a fuller version of this pattern — nine strange dreams, nine embarrassing readings — and concludes with the teaching that dreams follow their interpreter. A dream is not a fixed code. It is a blank wall on which the dreamer and the interpreter together project an image. What is in the dreamer's life will surface, one way or another, in what gets said aloud.
The exemplum, preserved as no. 217 in Moses Gaster's 1924 The Exempla of the Rabbis, is a warning as much as a story. The Rabbis believed dreams could reveal hidden things, but they did not believe dreams were innocent. A person who came to a sage with a dream was handing the sage a map — and a Rabbi as sharp as Yishmael could read, in the twists and rivers of the map, the places the dreamer had actually walked.
A quiet teaching: do not bring your dreams to a sage you cannot bear to be known by.