Here is another story to make this idea more clear ( there are many similar stories)
Reb Mendel Futerfas was the spiritual mentor of the city of Kfar Chabad in Israel. But in the 1940s, he was imprisoned and finally exiled to Siberia by the Soviet government. His crime: teaching and practicing Judaism.
On his birthday one year in Siberia, Reb Mendel longed to celebrate in the Chasidic manner by gathering with one’s friends, making an account of the past year and good resolutions for the upcoming year, and by having a private audience with the Rebbe.
Reb Mendel’s only “friends” in Siberia were the boorish Cossacks and political prisoners with whom he was exiled. A Chasidic gathering he could not make. But what he could do was to have a private audience with the Rebbe — in his mind.
Reb Mendel made the customary spiritual preparations for the communing of his soul with the Rebbe’s.
He then pictured himself writing a note to the Rebbe with all of his requests for blessings for the coming year. He imagined himself giving the note to the Rebbe and the Rebbe reading the note.
Then, in his mind’s eye, the Rebbe assured him that everything would be well.
Reb Mendel felt encouraged and strengthened.
Years later, when Reb Mendel was released from Siberia, he joined his wife and children who had meanwhile moved to England.
One day, as Reb Mendel perused the correspondence that his wife had received from the Rebbe in his absence, he came across a telegram.
The telegram’s date was the day after Reb Mendel’s birthday, years before. The Rebbe had sent Mrs. Futerfas a telegram to notify her that, “I received your husband’s letter…”
No distance, physical, spiritual, or medical, can separate a Jew from the Rebbe.
(a slightly different version: Years later, after he was released and united with his family, his wife showed him a strange letter that she had received from the Rebbe. The Rebbe had written her several letters but all were addressed to her and this one was addressed to Rav Mendel although he was in Siberia far from home at the time.
He read it and also at first didn’t understand, until he noticed that the date on the letter was the same as his birthday six years ago, the same day he had imagined his ‘Yechidus’. When he read it again he saw that it
contained answers to all the questions he asked, in the order that he had asked them. The Rebbe was with him.