"Injustice is the perverse root of poverty," Pope Francis said Sunday at a Mass marking the Roman Catholic Church's Day of the Poor.
Francis invited thousands of poor people to Saint Peter's Basilica for the Mass and he is scheduled to have lunch with them later.
"The cry of the poor daily becomes stronger, but heard less, drowned out by the din of the rich few, who grow ever fewer and more rich," Francis said.
He also made a reference to migrants when he called on people to pay attention to "all those forced to flee their homes and native land for an uncertain future."
The leader of the world's Roman Catholics said, "Let us ask for the grace to hear the cry of all those tossed by the waves of life."
Sunday is the second observance of the Day of the Poor, an event that Francis initiated last year.
In addition to lunching with the poor after Mass, Francis has gathered a team of doctors who will provide free medical care to the poor.
The French news agency, AFP, reports doctors treated 600 people last year at the first World Day of the Poor.