The Lubliner Rebbe asked “How is it possible that one may do teshuvah on Shabbos?  After all, when doing teshuvah on Shabbos, one carries all the sins of the secular world into the kedusha of Shabbos, which is like carrying from a public domain into a private domain.  And on Shabbos, moving things from a public to a private domain is forbidden.”

“Not so.  For doing teshuvah is a life-saving process, and when it comes to saving a life, we are required to violate the law of Shabbos.” ~ Zikaron Zos as quoted by R’ Dovid Meisels