The scene is years ago in Israel shortly after the second destruction. The great sage and Holy saint Rebbe Elezar (the son of Rabbi Shimon Bar Yochai; grand master Kabbalist and author of the Zohar) was walking with his holy friends in an open field discussing deep mystical secrets found in some sentence of the Torah. It was a very hot day and they were pleasantly surprised when they came upon a remarkably beautiful spot carpeted with flowers and shaded by gracious trees.
"How pleasant is this place" said Rebbe Elezar. "Let us sit here to rest."
They were just beginning to enjoy the shade when suddenly they heard a rather loud rustling sound approaching them rapidly and they all turned to look. Several of them almost fainted from shock; it was a huge snake, back arched like a bow speeding towards them in the distance.
But Rebbe Elezar seemed to know exactly what to do; he stared at the serpent for a few seconds, stood his full height and shouted "Nachash Nachash! (Snake, snake) The man you are going to kill has repented! Turn back!"
"What is this?!" Asked one of the group by the name of Rabbi Abba. But Rebbe Elezar motioned for him to be still and again commanded the snake "Nachash Nachash! (Snake, snake) The man you are going to kill has repented! Turn back!"
But the snake, although he seemed to slow down a bit, did not stop. But Rebbe Elezar seemed to be expecting this.
"Nachash Nachash!" He yelled. "You should know that just over that hill there is an evil murderer sleeping. He just beat a Jew almost to death and stole all his money. Go kill him instead."
When the snake heard these words he stopped, reared up frighteningly and shot off in the direction that Rabbi Elezar spoke of.
After the snake was gone the other Rabbis gasped in relief and began to ask for an explanation. Rebbe Elezar replied.
"Know that that snake had been commanded by G-d to kill a certain Jew that had transgressed some serious crimes. I know this because my holy father taught me to recognize and understand such things.
"But the snake didn't know that this Jew repented completely of his sins, resolved to return (Tshuva) to his true Jewish soul and do what G-d wants.
"I know this because I saw a spirit intercept the snake and announce this to him. But the snake was bloodthirsty and refused to listen. It claimed that it was sent by G-d and didn't have to listen to spirits. But then the spirit whispered to him about the murderer and I heard that also. Now let us go and see even greater wonders.
They walked for almost an hour in the direction the snake took until they came upon a horrible sight. The snake was wrapped around the neck of a man he had obviously just killed and was biting him over and over again. Rabbi Elezar approached the scene, bent down, picked up a small leather pouch that was lying in the grass nearby, turned to his companions and said. "Here is the money this murderer stole from the poor Jew. Now I will explain what happened.
"The snake was still not convinced by the spirit. But when I told the snake he did listen because I have the power of the Torah; namely the sentence in Isaiah (43:4)
"Since you were precious in my sight and I love you, so I will give a person in your place …..."
"Which means that when a person makes himself precious to G-d namely he does 'tshuva' and returns to the Creator, then, even if he deserved death, he becomes beloved.
"But what can be done if the angel of death has already been sent to punish that person? On this the sentence concludes 'I will give a person in your place'. In other words G-d finds an evil person, one who is devoted to the 'side' of death, to take the place of this penitent."
Before Rebbe Elezar finished his explanation not far from them a battered Jew, who seemed not to have noticed them, hobbled over to a large rock, sat himself down, put his face in his hands and began to weep. The wind was blowing in their direction and carried his voice.
"Master of the Universe! You know that I don't care about what happened to me. Whatever you decide to do to me is just and right. But my parents! Please, HaShem! My old father and mother! What will be with them! They'll starve! Now I won't be able to provide for them. And some of the money belongs to a pauper who needs it to marry off his daughter! G-d. have mercy!" And he broke into uncontrollable weeping.
"You see," Rebbe Elezar continued. "I told you there would be more miracles!"
He led them to the moaning Jew and when he showed him the moneybag with everything he lost in it the poor fellow was beside himself with joy and thanks to the Rabbis and to G-d. Rebbe Elezar then healed the fellow's wounds by praying for him and then took him and the company back the dead thief with the snake still wrapped around him biting him to shreds.
"Nachash Nachash!" Commanded Rebbe Elezar. "Up to now everything you did was with the consent of Heaven. Enough! I now command you to retreat to your cave and never harm another human your entire life!"
With this the snake immediately left his victim and slithered off into the distance.
"In the pocket of this murderer you will find another pouch" he said to the fellow they had just helped. Take it and give it to (he gave him the details). This thief's son is also a thief like his father. He stole this money from the father of the fellow I am asking you to give it to."
"All that has happened today" Said Rabbi Elezar to the others. "is completely incomprehensible to me. It is not because of my wisdom rather my soul somehow saw all this and it was as though it was all obvious."
(original article: http://www.ohrtmimim.org/Torah_Default.asp?id=2297)