Bishop P. Francis Murphy, auxiliary bishop of Baltimore, will celebrate the 9:30 a.m. Mass Christmas at Springfield Hospital Center in Sykesville.
The service, which is open to the public, will be in the auditorium of the Big G building at 6655 Sykesville Road.
In his homily, Bishop Murphy will relate the story of the first Christmas to the world today.
"The Christmas story that challenges me most deeply is the fact of the homelessness of Mary and Joseph," he has written for his sermon. "It is a story being repeated again and again in our own society."
The bishop, who is Western vicar in the archdiocese, said the state's five western counties have 12,000 families living in substandard housing and lacking basic amenities.
Five years ago, the bishop helped form the Western Maryland Interfaith Housing Development Corporation to help alleviate housing shortages. The group, of which he is president, manages more than 200 units and is negotiating for 64 more.
In his Christmas message, Bishop Murphy will ask for more aid to the homeless.
"Join us to make a difference for the many Marys and Josephs seeking shelter in our midst," he will say.
Information: 795-2100.