A widow once came to Rav Aharon of Karlin zy”a and cried that her daughter was engaged but the groom warned that if he was not given the dowry on time, he would not go ahead with the wedding. Rav Aharon immediately gave her his Shabbos candlesticks. She sold them for a lot of money, which she used for the dowry.
A few days later, she came back and said that her daughter was unwilling to get married without a nice wedding dress. The Rebbe got up and went over to the drawer where he kept all of his money. He had exactly 18 silver coins saved up, and he gave it all to her.
After she left, the Rebbitzen walked in and asked, “Aren’t there at least 18 poor families in our town? You could have given one silver coin to each poor family and thereby benefited many people. Why did you give it all to one woman for a need that doesn’t seem all that important?”
Rav Ahaon replied, “When I stood by the drawer, I had the same thought. But I told myself: If I really care about those other families so much, why didn’t I think about them until now? Why didn’t I give them this money yesterday?
“I then understood that these thoughts were coming from the yeitzer hara. It is true that he may have had a good point, but I don’t want to listen to the yeitzer hara even if he is right, as this certainly won’t lead to any good outcome.”
This can be explained with a moshol: The lion, the king of the jungle, got sick, and all of the other animals searched for a cure for his illness. They knew about a certain type of grass that could be used to heal the lion, but it only grew inside tiny holes in stones and none of them could reach it.
Finally, the snake said that he could wiggle into the small hole and take out the grass. The lion, however, would not agree. He said, “I would take the medicine from the hand of any other animal but not from the snake because he will mix his poison into the medicine...”
Reprinted from The Way of Emunah – The Collected Torah Thoughts of Rabbi Meir Isamar Rosenbaum – Parshas Pekudei 5785