Rabbi Perida had a student who was extraordinarily slow to learn. While other pupils grasped a teaching after hearing it once or twice, this student required something far more extraordinary. Rabbi Perida would repeat each lesson four hundred times before the young man understood it.
The Talmud in Eruvin (54b) preserves this remarkable tale. Four hundred repetitions—not ten, not fifty, but four hundred. And Rabbi Perida never once lost his patience, never once raised his voice, never once suggested that the student was wasting his time.
One day, after completing the four hundredth repetition, the student still did not understand. Rabbi Perida noticed that the young man seemed distracted. "What is troubling you today?" he asked gently. The student confessed that he had heard someone was waiting to see the rabbi, and his anxiety about taking up too much time had shattered his concentration.
"Do not worry," Rabbi Perida said. "Let us begin again." And he repeated the lesson another four hundred times—eight hundred repetitions in total for a single teaching.
A heavenly voice then rang out and offered Rabbi Perida a choice: he could have four hundred years added to his life, or he could be guaranteed that he and his entire generation would merit a place in the World to Come. Rabbi Perida chose the World to Come, reasoning that years of life would eventually end, but eternal reward would last forever.
God was so pleased with this answer that He granted both rewards. The Maase Buch records this story as a model of patience in teaching—proof that repetition is not failure, but the deepest form of devotion to learning.