King Shapur of Persia once asked the sage Shmuel: "Tell me what I will see in my dream tonight." It was a test — could a Jewish sage truly predict what a foreign king would dream?
Shmuel replied: "You will dream that the Romans are coming upon you. They will capture you, and they will force you to grind date-pits in a golden mill." He described the dream in precise detail — the Roman soldiers, the humiliation, the golden mill.
King Shapur spent the entire day thinking about Shmuel's words. That night, he dreamed exactly what Shmuel had described. The Romans, the capture, the golden mill — every detail matched.
The Talmud (Berakhot 56a) also records a parallel incident. The Roman Caesar asked Rabbi Yehoshua ben Hananiah the same question: "Tell me what I will dream tonight." Rabbi Yehoshua told him he would dream of the Persians coming to attack him, capturing him, and forcing him to tend unclean animals with a golden staff. The Caesar thought about it all day and dreamed precisely that.
The lesson of both stories is the same: dreams are shaped by what occupies the mind. Neither Shmuel nor Rabbi Yehoshua had prophetic power over dreams. They had something better — they understood psychology. Tell a person vividly enough what they will dream, and the mind will produce exactly that image. The sages' power over kings came not from magic but from their understanding of the human mind — a form of wisdom the kings themselves did not possess.