Yosef Karo

“ Paragraph 6 - Regarding non-Jews who besiege Jewish cities: if they come for money, we do not desecrate the Shabbat [to protect ourselves] , but if they came to kill or come with no presented reason, we go out with weapons and desecrate the Shabbat. In a city that is near the border, even if they just come for straw or hay, we desecrate the Shabbat. ”

“ Paragraph 1 - All cases of saving a life supersede Shabbat, and he who hurries in these matters is praised. Even if there is a fire in a different yard and there is concern that it will move to this yard and cause danger, we put it out to ensure that it does not spread. ”

“ Paragraph 8 - One who sees a boat with Jews that is endangered at sea or in a flowing river, or an individual being chased by idolaters, it is a commandment to desecrate Shabbat to save them. (And see above at the end of chapter 306 regarding whether one desecrates Shabbat if someone wants to rape him.)
סעיף ח - הרואה ספינה שיש בה ישראל המטרפת בים, וכן נהר שוטף, (וכן) יחיד הנרדף מפני עובד כוכבים, מצוה על כל אדם לחלל עליהם שבת כדי להצילם (ועין לעיל סוף סימן ש"ו, מי שרוצים לאנסו, אם מחללין עליו שבת) . ”