Pope Francis called on humanity Sunday not to let sadness prevail because of the many forms of violence afflicting the world.<br />Francis cited no specific violent event in his homily in a Rome basilica, St. John in Lateran.<br />But he said: "We can't let ourselves be overcome by weariness.<br />No form of sadness is allowed, even if we would have reason to, because of the many worries and multiple forms of violence which wound our humanity."<br />The ceremony was part of the special church Holy Year highlighting his emphasis on the importance of mercy and pardon.<br />Since being elected pontiff in 2013, Francis has tried to reshape the image held by many of the Roman Catholic church as one defined largely by rigid dogma.