A Baltimore priest is known for his spirit of welcome. After three decades, he now will say goodbye. Jonathan M. Pitts BALTIMORE —When Nathalie Piraino first wandered into a service at St. Matthew Catholic Church in Northeast Baltimore, she was carrying the kind of burden few human beings are ever called upon to handle. A native of Rwanda, she had learned months earlier that dozens of her family members, including her mother and siblings, had been slaughtered in the genocide then consuming the small African country. As the Mass began, the Rev. Joseph L. Muth Jr. did what he always does: asked whether any newcomers were present, walked his microphone down from the altar, and asked them to tell their stories.