Pope Francis has wasted no time settling into his new role as head of the Roman Catholic Church.

Delivering his first Mass inside the Sistine Chapel, his homily was simple --- He urged cardinals to stick to their Gospel roots, shun modern temptations. If they didn't, he warned the church would fail at its true mission.

"We can walk all we want, we can build many things, but if we don't proclaim Jesus Christ, something is wrong. We would become a compassionate NGO."

Speaking in Italian and without notes, his approach had the homespun quality of a sermon from a parish priest. It was a stark contrast to his predecessor Pope Benedict who read his out in Latin.