Rabbi Pereda had a pupil who was very stupid, and whatever he taught him had to be repeated

400 times before he remembered it. One day Rabbi Pereda had repeated the lesson 400 times,

when he was called away on some religious business and the pupil had not yet learned the lesson.

Said R. Pereda to the pupil: "How is it that you know less now than at other times although I have repeated the lesson 400 times?"

The pupil replied: "As you were called away, my mind was distracted and I paid no attention, for I was thinking, 'Now the teacher is going away'."

Then R. Pereda said: "Now pay attention, I will repeat it again 400 times."

And he repeated the lesson with him 400 times until he knew it. Then a voice came from heaven, saying: "Do you prefer to live 400 years more or to enter paradise at once with your generation?"

R. Pereda replied: "I prefer to be taken into paradise with my parents."

Then the Lord, blessed be He, said: "Give the good man both, paradise and 400 more years of life."

Therefore, dear friends, be patient with your pupils.