Before Reb Menachem Mendel of Vitebsk embarked on his journey to the Holy Land, he went to receive a farewell blessing form Reb Yaakov Yosef of Polona. The Alter Rebbe, who was then a young man, accompanied him.
Reb Yaakov Yosef had been present at Reb Menachem Mendel's first meeting with the Baal Shem Tov. "Do you remember the story the Baal Shem Tov told you?" Reb Yaakov Yosef asked. "In that story, he implied that you would journey to the Holy Land," he continued.
"Yes, and I am on my way there."
"The Baal Shem Tov also implied that you would come to me for a blessing."
"That is the purpose of my visit."
"That story also implied that you would be accompanied by a young man whose greatness will be acknowledged everywhere."
Reb Menachem Mendel presented the Alter Rebbe before Reb Yaakov Yosef. "This is he," he declared.