Eiruvin 44b: All those who go out to save lives may return to their places.
עירובין מד ע”ב: כל היוצאים להציל חוזרין למקומן.
וכתבו התוס’ שם הא דלא חשיב ליה בפ״ק דביצה (דף יא:) גבי הנך ג׳ דהתירו סופן משום תחילתן דזה אינו חידוש וכל הנהו צריכי כדאמרינן התם. ומזה למד הגר”מ פיינשטיין (או”ח ח”ד סימן פ’) דכל היוצאין להציל לא מיירי דוקא במלחמה שיש סכנה גם לאחר שנצחו, אלא אפילו בחכמה הבאה לילד וכדומה שלא יהיה עוד סכנה ובכל זאת התירו סופן משום תחילתן.
There is a doctor in Beilinson Hospital in Petach Tikvah who became observant 30 years ago. This is his story. A religious Jew called him on Shabbos to come and take care of his sick wife. When the doctor arrived at his door and saw that the man was religious, he said, “I’m afraid if treat her, you won’t pay me after Shabbos. Either pay me on Shabbos, or find another doctor.” The man said, “Yes, I’ll pay you on Shabbos.” So he treated the man’s wife, and then said, “You own me 250 shekel.” The man took out his checkbook and wrote a check for 1000 shekel. The doctor was puzzled, so the man explained: “The word אלף (1000) is only 3 letters while מאתים וחמשים (250) is 11 letters. I wanted to minimize my chillul Shabbos.” The doctor took the check and left.
On Thursday he called the man back and said, “I must tell you that I couldn’t sleep for the last few nights, I was in awe of your dedication for Shabbos. My wife and I have decided that we want to learn more about Shabbos. Can you teach us?” [This is based on the Tosafos in Eiruvin quoted above, which says that chillul Shabbos after the life has been saved is permitted because of the rule that “they permitted the end to facilitate the beginning”: if the people going out to save lives knew that they would not be allowed to return home, they might not go to save lives in the first place. This is the basis of R’ Moshe’s heter for Hatzolah members to drive home after a call – Igros Moshe O.C. 4:80. Here too, if this man had not paid the doctor, he would not go to help the next religious Jew who called him on Shabbos. Here the heter is more clear, since the doctor made that condition explicitly.]