The following story is related in Sefer Devarim Areivim:
There once was a young talmid chochom whom the yeitzer hara wanted to draw away from the proper path. One night, it came to his window and said, “Let me in. I am an angel sent from Heaven to teach you Torah.” The talmid chochom replied that he wanted to put in the effort himself to learn, so he didn’t need his help. This went on night after night. The yeitzer hara tried to gain entry to no avail. Finally, he said, “If you don’t want my help, at least let me give you a gift.”
It left a closed and locked box outside the window for him and said, “This will be your source of salvation and success. If a person ever comes before you in need of success or anything else, go to this box, pray to Hashem, and present your request, and it will succeed every time to grant everyone whatever they need. Just make sure to never open this box, for it is full of amulets and holy names.”
The young scholar thought to himself: What harm could there be in doing good for others? And he accepted this gift. The yeitzer hara then sent many people to him with various requests. The young scholar used this box for each person, and it always was successful. This created a great commotion, and this talmid chochom became known as a miracle worker.
When Rav Elimelech and Rav Zushe heard about this, they went to visit this young scholar. When they arrived in his city, they sent a message for him to come to them. They knew that this would be a clear sign for them: If he came to them, then he was truly a God-fearing scholar, but if he refused to come to them, it was a sign that he was not using the side of good.
Indeed, the young scholar came before them, and they asked him how he did what he did. He recounted to them everything that had happened to him, and the holy brothers understood what had occurred. They made a circle around him and used holy means to ensure that nothing would harm him. They opened the box and saw that there were snakes and scorpions in it. They neutralized the snakes and scorpions, and the young scholar remained God-fearing as before.
