Rav Yosef Shalom Elyashiv’s grandfather was R’ Shlomo Elyashiv, better known as the Leshem. The Leshem’s sefer is based on writing from the Arizal and Vilna Gaon, and is very difficult to understand. His sefarim are so precious that when the Leshem sent a copy to one of the great Kabalist, the Ben Ish Chai, the latter put on his Shabbos clothing, lit candles and recited the shehecheyanu blessing upon receiving it.
The Chofetz Chaim told a rav “When you pass through Shavel, make it a point to go see the Leshem. In this world we are still able to see him, but in the next world who knows if we’ll be able to approach him altogether.” On another occasion, the Chofetz Chaim said the following of the Leshem, “Everyone has the ability to build [spiritual structures] in this world, but the Leshem is unique because he can build in the upper world while living in this world.” That was just an introduction to the following story:
The Leshem’s daughter, Chayah Musha and her husband, Rav Avrohom, remained childless for 17 years after their marriage. After visiting with a doctor who had studied all the tests, she was informed by telegram that there was no way she will ever have children. The doctor told her, “The day I grow hair on the palm of my hand – that’s the day you will have a child.”
Chayah Musha did just what any other Jewish wife would be expected to do: she sought comfort in her Tehillim. She went down to the cellar with it in order not to disturb her father’s learning and started crying to Hashem, “Please grant us a child!”
Her father, the Leshem, stepped out of his room for a moment and suddenly heard a woman crying from afar. He listened carefully for a moment and then exclaimed, “That’s my daughter Chayah Musha!” He went down to the cellar and found his daughter with a Tehillim in her hands, crying her heart out. The Leshem felt helpless; he could only stand and watch. He called out, “Chayah Musha! Why are you crying?” In between sobs, she explained how she just received a telegram from the doctor informing her that she would never be able to bear children. “So what are you doing in the cellar with your Tehillim?” he asked her.
“I didn’t want to interrupt Tatte’s learning,” she said.
Upon hearing that, the Leshem said, “Until now, there was no natural way or means for you to bear children, but since you sacrificed your feelings to such a degree and refused to distract me from my learning, I bless you that within the year you will have a child, one who will grant you much nachas.” Chayah Musha whispered Amen through her tears.
Around 9 months later, HaRav Yosef Shalom Elyashiv, who would one day become the gadol hador, was born.