The chossid Reb Zalman Gurary once had an audience with the Lubavitcher Rebbe to request a blessing for the success of an upcoming surgery.
When he told the Rebbe what he was his seeking, the Rebbe responded “why ask simply for a successful surgery, if you can request that you won’t need the surgery to begin with?”
Immediately he altered his statement and appealed to the Rebbe that he bless him that he not need a surgery at all.
The Rebbe responded that now it was too late but “if you pass over the threshold (of my room) with simple faith, you can accomplish anything.”
