During a season of Roman persecution, two disciples of Rabbi Yehoshua ben Chananyah disguised themselves in Gentile dress and tried to pass unnoticed through dangerous territory. They were recognized anyway by an officer who had seen them before.
The officer did not immediately arrest them. He engaged them in debate. He asked them three specific legal and theological questions, questions he had evidently asked of Rabbi Yehoshua on an earlier occasion. Perhaps he was testing whether they truly belonged to the master they denied, or perhaps he was curious to see whether the students had absorbed the teacher's reasoning.
The two disciples answered each question in precisely the way Rabbi Yehoshua himself had answered it. Word for word, argument for argument, the same three replies came out of their mouths.
The Book of Exempla, compiled by Moses Gaster in 1924 from medieval Jewish manuscripts, preserves the brief notice as example no. 65. The story is one sentence long and contains no moral in the text itself. But the implied moral rings through the brevity.
A disguise can be stripped off. A memorized answer can betray you. The students were known by their thinking. What they had learned from their master was not a set of conclusions. It was a way of walking through a problem. The officer heard Rabbi Yehoshua in their mouths, and a teaching that had been delivered in a classroom returned, unaltered, in a roadside interrogation. That is what real learning looks like.