When practitioners are directly persecuted by evildoers, they can use supernormal powers to stop the persecution while punishing and warning the evildoers. In this way practitioners can clearly distinguish themselves from other people, and it is also a form of mercy to awaken the foolish evildoer. Below is an excerpt from the cultivation story of Buddha Milarepa that talks about the issue of transferring illness.
Master Milarepa appeared to be seriously ill. At that time, the doctor Caopu brought many fine wines and meats to pretend to provide him with support. When he went before Master Milarepa, he laughed at Master Milarepa, "Ha! Such an accomplished person like you should not get seriously ill! How did you get sick? If the illness can be divided and given to others, you can distribute it to your disciples. If the illness can be transferred, please transfer your illness to me! You are in such a quandary--what are you going to do?"
Master Milarepa smiled serenely, "Actually, I do not have to have the illness. You should be very clear about why I am ill right now. The reasons for an ordinary person's illness and a Yoga master's illness are different. The natures of their illnesses are different as well. Right now my appearance of being ill is actually a display of the solemn nature of the Buddha Fa."
Caopu thought that it was quite unlikely that illnesses could be transferred, like Milarepa said they could. How could illnesses be transferred to others? So he said, "I am uncertain about the cause of Master's illness. If it's caused by evil possession, you should exercise the power of expelling the evil. If it is caused by the disharmony of the Four Elements (i.e., Earth, Fire, Water and Wind), you should adjust your body and take medicine. If the illness can really be transferred to others, then please transfer it to me."
Master Milarepa said, "There is a person with great sins, and the evil in his heart came to harm me. It caused the Four Elements within me to fall into disharmony and for me to fall ill. I don't think you can eliminate it. Although I can transfer this illness to you, you won't be able to withstand it even for a moment. So it's better not to transfer it to you."
Caopu thought, "He can't transfer the illness to others at all, and that's why he's coming up with so many excuses. I'll indeed make a fool of him!" So he repeatedly insisted on Master Milarepa transferring the illness to him.
Master Milarepa said, "Since you insist on it, I will temporarily transfer the illness to that door over there. If I transfer it to you, you cannot withstand it. Watch!" Then Master Milarepa used supernormal power to transfer the illness to the door. The door creaked at first, as if it was going to break, and after a while, the door really did crack into many pieces. At this moment, Master Milarepa indeed looked healthy again.
Caopu thought, "This is just an illusion that he conjured up! It cannot fool me." Then he said, "Great! This is really extraordinary. But please transfer the illness to me, Master."
Master Milarepa said, "Since you insist on it, I will transfer half of the illness to you. If I transfer all of it to you, you definitely cannot withstand it!" Then he transferred half of the illness to Caopu. Caopu immediately suffered from great pain and he nearly fainted. He could not even tremble or breathe. When he nearly died, Master Milarepa took back most of the illness and asked him, "How do you feel after I transferred less than half of the illness to you? Can you withstand it?"
After going through the great pain, Caopu started to feel genuine remorse. He knelt down, bowed under Master Milarepa's feet and cried, "Master! Master! Sage! Sage! I sincerely repent! Please forgive me. I want to use all of my wealth to pay homage to you. Master, please help me with my sins and debt!" Caopu cried from deep within.
Master Milarepa saw that Caopu was sincerely repenting, and he was very pleased. He took back the remaining illness and then said to Caopu, "In my whole life, I have never wanted any wealth, much less now, when I am going to die soon. You can keep it for yourself. After this, please never do evil things again, even at the peril of your life. I promise to eliminate the karmic retribution caused by your sin this time. "
Caopu said to Master Milarepa, "The root cause of my evildoing before was mostly my pursuit of wealth. Now I don't need it anymore. Although Master doesn't need it, your disciples at least need money and food for cultivation practice. Please accept my wealth for your disciples." Even though he begged like this, Master Milarepa still didn't accept his wealth. Later his disciples finally accepted the wealth and used it to provide support for their congregation. Even now, it is still a tradition to support the assembly meeting in Quba, Tibet. Thereafter, Caopu really gave up his lifelong attachment to wealth and became a very good cultivator.
(Selected from "Buddha Milarepa's cultivation practice story" http://minghui.org/mh/articles/2000/12/31/5862.html)