Yisrael Salanter was a rabbi who lived a long time ago in a place called Lithuania. He was a religious teacher who taught people how to live a good and holy life based on how it said in the Bible. He taught that it wasn't enough just to follow the rules in the Bible, but he said that people should try to have good feelings and thoughts, and do things to help other people. He also said that people should learn how to be better at controlling their behavior, and try to be kind and generous.