MADRID — The Rev. Eubilio Rodríguez’s church is a prefabricated building in an area of this city hard hit by Spain’s economic crisis. In front of the altar are a few scraggly potted plants. Behind it, some plastic chairs.

How, he asks, can the Roman Catholic Church be getting ready for a lavish $72 million celebration in this city — some of it paid for with tax dollars — when Spain is in the midst of an austerity drive, the unemployment rate for young people is 40 percent and his parishioners are losing their homes to foreclosure every day?

“It is scandalous, the price,” he said. “It is shameful. It discredits the church.”

Father Rodríguez, 67, is among the 120 clergymen working among the poor here who have signed a lengthy petition deploring the pope’s visit this week on many grounds — from its cost to what they see as an inappropriate melding of church and state.

Madrid is girding itself for the arrival of perhaps one and a half million pilgrims. Its lampposts are gaily decorated with banners. Retiro Park has been decked out with 200 portable confessional booths. But bitter debates are raging over the festivities and the role of the church in Spanish politics.