He had lunch at the city's historic San Vittore prison, where all 893 inmates – men and women – are awaiting trial.

But Pope Francis began his visit March 25 on the outskirts of the city, at the "White Houses," a housing development for the poor built in the 1970s. Three families welcomed the Pope into their apartments: Stefano Pasquale, 59, who is ill and cared for by his 57-year-old wife, Dorotee; a Muslim couple and their three children from Morocco; and the Onetes.

Nuccio Onete, 82, was home for the Pope's visit, but his wife, Adele, was hospitalized with pneumonia three days earlier, so the Pope called her on the telephone.

The people of the neighbourhood gave Pope Francis a handmade white stole, which he put on before addressing the crowd.

The fact that it was homemade, he said, "makes it much more precious and is a reminder that the Christian priest is chosen from the people and is at the service of the people. My priesthood, like that of your pastor and the other priests who work here, is a gift of Christ, but one sewn by you, by the people, with your faith, your struggles, your prayers and your tears."

Arriving next at Milan's massive Gothic cathedral, Pope Francis met with the archdiocese's pastoral workers and responded to questions from a priest, a permanent deacon and a religious sister, urging them to trust in God, hold on to their joy and share the good news of Christ with everyone they meet.

"We should not fear challenges," he said. "It is good that they exist" and Christians must "grab them, like a bull, by the horns."

Challenges "are a sign of a living faith, of a living community that seeks the Lord and keeps its eyes and heart open."

Asked by Father Gabriele Gioia about evangelization efforts that do not seem to result in "catching fish," Pope Francis said the work of an evangelizer – of all Christians – is to set out and cast the nets. "It's the Lord who catches the fish."

Preoccupation with numbers is never a good thing, Pope Francis said.

Responding to Ursuline Sister Paola Paganoni, who spoke of the challenge of reaching out when so many orders are experiencing an aging and declining membership, the Pope spoke as a Jesuit, saying, "The majority of our founding fathers and mothers never thought they'd be a multitude."

Rather, he said, they were moved by the Holy Spirit to respond to the real needs of their time and "to build the church like leaven in the dough, like salt and light for the world."

Just think, he said, a dish with too much salt would be inedible. And, "I've never seen a pizzamaker who took a half kilo of yeast and 100 grams of flour to make a pizza. No, it has to be the opposite" proportion. Christians must be concerned with being leaven in society more than with being a majority.

It is not up to the Pope to tell religious orders what their focus should be, he said. They must look to their founding charisms and the guidance of the Holy Spirit. But in all they do, he said, "ignite the hope that has been extinguished and weakened by a society that has become insensitive to the pain of others. Our fragility as congregations can make us more attentive to the many forms of fragility that surround us and transform them into spaces of blessing."