(ANSA) - Vatican City, December 19 - Pope Francis on Thursday preached a message of humility at his Vatican residence. "Humility makes us fruitful, whereas pride makes us sterile," said the pontiff in a morning Mass. "We can't do it by ourselves," he added, admonishing believers to turn to God for help. "Many have dared to think they could save themselves. Even Christians! "But all is grace. Only God can help us on the path to holiness".