The Taamei HaMinhagim writes, העולמות בכל רב שפע יושפע, “A great bounty [of parnassah, etc.] should come to all worlds” is roshei teivos, י"רשב.
The Yerushalmi (Brachos 9:18) writes, "Whenever Reb Shimon needed money, he would say, 'Valley! Valley! Fill up with gold coins,' and that would happen."
A yungerman was in Meron rosh chodesh Iyar and davened for parnassah. And then he said, uncharacteristically, "Ribono Shel Olam, show me that You accepted my tefillah." Immediately after this tefillah, he received a phone call. The caller told him that he was sending him thousands of shekalim.
A wealthy businesswoman from Eretz Yisrael came to Reb Shimon bar Yochai's tzion to daven. She was about to ship a boatload of merchandise, and she davened that it should reach its destination and that she should be successful in this business venture. At first, she couldn’t approach the tzion because another woman was in front of her praying loudly, asking for three hundred rubles to marry off her child. The wealthy woman took out three hundred rubles from her purse and gave it to the woman. This was the only way she could get to the tzion. Standing before the tzion, she said, "Reb Shimon! The woman who was here before me received her request. She prayed for three hundred rubles, and she received that amount immediately. May my requests also be answered as quickly."
The Divrei Shmuel zt'l repeated this story and expressed that the wealthy woman wisely recognized that the woman in front of her didn’t receive three hundred rubles because she gave it to her. She understood that the salvation came from the poor woman's tefillos!
A poor man was shouting at the kever of Reb Shimon, "Reb Shimon! Send me fifty thousand dollars." The loud, bitter shouts disturbed the peace of mind of a wealthy person beside him. This rich man had come from America to be in Meron for Lag b'Omer, and here there was a person who was not letting him daven as he hoped he would. He decided to play a prank on him. He asked him for his address, and after Lag b'Omer, he mailed him a fifty-thousand-dollar check and signed it "Reb Shimon bar Yochai." That is what he thought he did. However, a couple of weeks later, when he saw his bank statements, he realized he had accidentally signed his own name. The check went through! He saw that the person's tefillos at Reb Shimon's kever were indeed answered.
Children and Refuah on Lag b'Omer
Tzaddikim teach that to bear children, one is advised to have kavanah by the brachah of רפאנו in Shemonah Esrei. The Shem Shlomo of Munkacz zt’l taught that Lag b'Omer is mesugal for refuah (as we will discuss), so Lag b’Omer is also mesugal for bearing children.
Lag b'Omer is also a good time to daven that his children should grow up erlich, with yiras Shamayim. The Gemara (Makos 17:) states that a mother should daven that her children should be like Reb Shimon bar Yochai. The Minchas Elazar (Shaar Yissaschar) says the Gemara refers to a person davening on Lag b'Omer. On this day, anything is possible. On this day, one can ask for the most incredible things – even that one's child be like Reb Shimon bar Yochai.
Parnassah
The Chasam Sofer (Yorah Deiah 233) makes the following calculation: Chazal tell us that when the Yidden left Mitzrayim, they ate matzos for thirty days. They finished the matzos on Pesach Sheini. The Midrash adds that they didn’t have food for three days, and then on the next day, the manna fell. According to this calculation, the manna first came down on Lag b'Omer. We understand that it is an ideal day to daven for parnassah.
