The Rebbe himself once told the following story:

“A letter arrived one day from a sick man in Israel. He was scheduled to undergo a complicated operation and he requested a blessing. Nu, when a Jew asks for a blessing, shouldn’t I help him?

“I gave him the blessing, adding that he should commit himself to putting on tefillin every day. The sick man resolved to do so and his condition suddenly took a sharp turn for the better. The doctors were surprised at the remarkable change. They canceled the operation and the incident became the talk of the department.

“As the word spread, many patients inquired what had caused the sudden recovery. The man told them that he began putting on tefillin.

“ ‘If that’s the case,’ they responded, ‘We will also begin performing this mitzvah.’ And indeed, many patients began to fulfill this daily obligation diligently.

“We can see from this,” concluded the Rebbe, “that the sick man’s stay in the hospital was intended to bring him and others to commit themselves to putting on tefillin. As soon as this mission was fulfilled, he was discharged.”