Adapted from a sppech by R. Shafran 3/6/99

The Gemara in Yoma states that it is allowable to break Shabbos to save someone's life. Because the Torah says "Es Shabsosai Tishmoru" My Sabbaths (plural), the Rabbis expound that we save his life so that he can keep many (plural) Sabbaths. This is according to Rabbi Shimon ben Menasye

The Meiri asks what about saving one's life for a few hours? The person has only a few hours to live. Will it be allowable to break Shabbos even though afterwards he will never be able to keep Shabbos again? The answer is that because in those few hours he will be able to do many mitzvos like saying the confession, reciting the shema, doing repentance for his past, etc. we are allowed to break Shabbos to keep him alive.

The Torah Or commentary asks a question. Those mitzvos that he will do in his last few hours do not include keeping Sabbaths. Isn't keeping Sabbath the mitzvah that we are allowed to break Shabbos for? We aren't allowed to break Sabbath to recite the shema or confess. The answer, according to the Torah Or, is that by repenting his sins in his last hours, he is in effect keeping many Sabbaths that he PREVIOUSLY broke. In that way, by keeping him alive a few hours, we are fulfilling the dictum of the sages, that he may keep many other Sabbaths.