Catholic cardinals and bishops must live to serve others as this is their vocation and path to salvation, Pope Francis has said."The vocation of sacred ministers, cardinals and bishops, as the word itself suggests, is to 'minister', or to serve," Francis said in a homily on Tuesday.He was speaking at a mass celebration in St. Peter's Basilica for prelates who have died this year."God served us first and the ministry of Jesus Christ, who came to serve, not be served, can only be that of a shepherd, ready to give his life for his flock."Those who dedicate themselves to serving and giving seem "losers" in the eyes of the world, Francis said, but in fact the opposite is true, he argued."Who does not live to serve, serves no purpose," he said, adding that "those who serve, redeem themselves".