Shaar Yissaschar writes that יוחאי בן שמעון is gematriya המתים מחיה.
The Minchas Elazar zt'l opposed the Zionist movement, which earned him some enemies. Once, as he was walking to Meron, he received a note that read, "If you dare go to Meron, you will be killed there." The Minchas Elazar told his gabbai, Reb Chaim Ber and Reb Asher Zelig Margolis zt'l, who were walking with him, "We are going to Reb Shimon; the malach hamaves is powerless there."
Famous story (because it happened in front of many people, and it is recorded in sefarim):
In the year 1918/ט"תרע, a childless couple davened in Meron at the kever of Reb Shimon bar Yochai and promised that if they had a child, they would bring him to Meron on Lag b'Omer for his chalakah (to make peyos).
They had a child, and when the child turned three, 1922/ג"תרפ, the mother brought the child to Meron as she had promised. Her husband remained home.
Lag b’Omer was on Friday that year, so most people remained in Meron for Shabbos. On Shabbos, the three-year-old child became ill with the cholera epidemic. On Shabbos morning, the mekubal Reb Asher Zelig Margolis zt'l was davening Mussaf before the amud, when the crowd heard the young child's loud shouts and cries. Everyone panicked, especially the mother, whose cries were heard above all others.
Reb Asher Zelig recorded this episode in one of his sefarim, and wrote, "The child was green; he seemed to be dead." The tefillah was over, but no one was interested in making Kiddush. A feeling of gloom reigned.
The mother took the child, placed him near the tzion, and said, "Reb Shimon! I brought my only son here at three years old to receive his first haircut, as I promised. Please, do not ruin my happiness and the happiness of my husband, who is waiting for us to return. Reb Shimon! I’m leaving my son here. Don’t embarrass me. Bring him back to health as he was healthy when I brought him here yesterday. Sanctify Hashem's name. Reveal to everyone that there is Hashem and that there are tzaddikim."
She left her son near the tzion and closed the door behind her. Only the child remained inside. A few minutes later, the child's voice was heard. He was calling for his mother. Reb Asher Zelig opened the door. The boy stood on his feet, calling, "Mother, I'm thirsty. Bring me water."
Everyone roared joyously, and they recited the brachah המתים מחיה.
