Story

Rebbi Aharon Kotler z"l is said to have had a hanhaga of carrying around the Chofetz Chaim's Mishna Berura with him wherever he went (like when he went collecting for the yeshiva, or traveling to do for Klal Yisrael). They once asked him the reason, and Rebbi Aharon answered: "I want the z'chus (merit) of the Chofetz Chaim!"