Pope Francis brought laughter to a group of young people gathered at the Vatican Nov.15 when he quoted an Argentinean comedian's metaphor about ham and cheese sandwiches in relation to the Christian life.

Speaking in Spanish, Pope Francis addressed the young people gathered for a symposium on prostitution and human trafficking, held at the Pio IV House at the Vatican on Nov. 15-16, and organized by the Pontifical Academy for Sciences.

He referenced a metaphor used by Argentinean comedian Luis Landriscina, "who explained the difference between collaboration and commitment. All of us have to collaborate, but Christians have to be committed. Landriscina said, 'The cow collaborates in our nourishment when she gives us milk. She gives milk which is made into cheese, and then we make a sandwich. But a sandwich with just cheese is a little bland, so we have to add a piece of ham. When it comes to the pig, the pig doesn't collaborate in making the ham, it gives its life, it commits'."

"To be committed to is to give one's life, to risk one's life, and life has meaning only if we are willing to risk it, to live it for the good of others. I like to see so many young people who want to be committed. Remember the ham and cheese sandwich!" the Pope said.

"Thank you for the work you are doing," the Holy Father continued. "It is a struggle we are all called to engage in, a struggle against that movement which is leading humanity to think that the person is an object that can be used and thrown away. An object to be used."

"We need to recover the dignity of the person," he continued. "We are certainly in an age in which the human person is used as an object and ends up becoming disposable material. In the eyes of God there is no disposable material, there is only dignity."

At the conclusion of the symposium, the chancellor of the Pontifical Academy of Sciences, Msgr. Marcelo Sanchez Sorondo, presented Pope Francis with a joint declaration against human trafficking signed by all the participants.