"One day, Rabbi Yehudah happened to be at a slaughterhouse when a calf that was being taken to the slaughter broke away and hid his head under Rabbi Yehudah's skirt, as if in terror. Rabbi Yehudah's response to the calf was, "Go, because this is what you were created for." In response to his heartless reaction to the frightened calf, it was decided in heaven that Rabbi Yehudah would have to learn compassion the hard way- through his own suffering.
From that day on, the Talmud recounts, Rabbi Yehudah was plagued by a horrible chronic case of kidney stones. His pain upon going to the bathroom was so severe that his neighbors timed the feeding of their noisiest animals to those times when Rabbi Yehudah went to the bathroom, hoping their cries would drown out his heart-wrenching screams.
One day thirteen years later, Rabbi Yehudah witnessed his household helper mercilessly sweeping a cat, or some say a weasel, out of the house. He beseeched her, "Be gentle with him for God's mercy is upon all his works." At that very instant, the Talmud tells us, Rabbi Yehudah's painful symptoms abated, his own compassion having aroused the compassion of the heavenly court."