NEW YORK - Pope Francis celebrated Mass for 18,000 people at the Madison Square Garden arena, the final event on his New York City trip.

Before the service began, Francis made a lap of the arena floor in a golf cart, getting huge cheers.

He waved, smiled and accepted some flowers and other gifts. On a second lap that took him down the middle aisle, he stopped at one point, apparently to bless some children.

By his preference, the pontiff sat in a simple oak chair built by day laborers working for a charity, rather than by expert craftsmen.

During the Mass, Francis emphasized a point he has made throughout his U.S. trip: the need to welcome foreigners and marginalized people.

In his homily he also cited "children who go without schooling, those deprived without medical insurance, the homeless, the forgotten elderly."

He says God "frees us from anonymity, from a life of emptiness and selfishness." He also says, "God is living in our cities," and so is the church.

He concluded the service with the customary "go in peace and serve the Lord" and added, "Please, I ask you, don't forget to pray for me."

The Mass was the last stop on Pope Francis' New York City trip. He left for Philadelphia Saturday morning.

The Associated Press Wire services contributed to this report.