VATICAN CITY (AP) — Pope Francis is urging people to resist what "the temptation to indifference" to suffering in a speech on the eve of a ceremony to formally proclaim Mother Teresa a saint.

Greeting thousands of lay volunteers from around the world in St. Peter's Square, Francis Saturday said that ignoring those suffering hunger, sickness or exploitation is a "modern sin, a sin of today."

The square hosts a ceremony Sunday expected to draw hundreds of thousands of admirers of Mother Teresa, a nun who before her death in 1997, cared for the destitute who were dying in the streets of India.

Among Saturday's crowd were firefighters and volunteers who rescued survivors from the Aug. 24 earthquake in central Italy.