One winter evening in Vilna, Rav Yisrael Salanter ZT”L was walking home late at night after teaching at the Yeshiva. He noticed that a store's exterior rolling shutter had been left open, likely forgotten by the shopkeeper. It had started to snow quite heavily, and the precipitation was beginning to seep into the store, threatening to damage the merchandise.
Many people would have simply continued walking - after all, it was late, cold, and the shopkeeper's carelessness wasn't their responsibility. Not Rav Salanter though, he spent several hours that night carefully removing merchandise from the areas of the store that could become wet from the snow.
The next morning, when the shopkeeper arrived, he was surprised to find that his merchandise was not damaged and that a note had been left explaining what had happened, signed by Rav Salanter. As an aside, Rav Salanter left a note detailing what he had done, likely to fulfill the Halacha that if one does a kindness to his friend without him knowing, he should inform his friend that he did the kindness. This serves to foster peace and harmony within Bnei Yisrael.
What makes this story particularly notable, is that the shopkeeper was known in the community (and to Rav Salanter) as one who had previously spoken negatively of Rav Salanter and his teaching methods. Despite this personal slight, Rav Salanter chose to spend hours in the cold to protect this man's merchandise and livelihood.
When later asked about his actions, Rav Salanter simply explained that protecting another person's property is not dependent on how he treats you - it is simply the right thing to do.
This story, which is well-documented in Jewish historical accounts, exemplifies the integrity in doing what is right regardless of personal feelings or convenience. It would become a teaching moment that his students would reference for generations to come about how true ethical behavior means doing what is right even when no one is watching and there is no personal benefit to be gained.
