ROME — Pope Francis told priests on Sunday to practice what they preach, saying the church’s credibility was on the line.

During a Mass to formally take possession of one of the Vatican basilicas in Rome, Francis said ordinary Catholics need to “see in our actions what they hear from our lips.”

Francis has made himself an example of a more humble and frugal church by refusing many of the trappings of the papacy, living in the Vatican hotel rather than the Apostolic Palace and wearing a simple white cassock of the papacy rather than fancy vestments and capes for formal occasions that his predecessors wore.

“Inconsistency on the part of pastors and the faithful between what they say and what they do, between word and manner of life, is undermining the church’s credibility,” he said.

Toward that end, Francis on Saturday took the first step toward following through on calls from cardinals that the Vatican be more responsive to the needs of the church on the ground, creating a group of eight cardinals from around the globe to advise him on running the church and reforming the Vatican bureaucracy.

The cardinals, from North and South America, Asia, Africa, Europe and Australia, include prelates with whom the former Cardinal Jorge Mario Bergoglio has long collaborated, including Cardinal Sean O’Malley, a Franciscan Capuchin monk who knows Bergoglio well and visited him in Buenos Aires.

Other members include representatives of regional bishops’ conferences, including Cardinal Oswald Gracias of Mumbai, India, who is the head of the Asian bishops’ conference.

The secretary of the group, Monsignor Marcello Semeraro, bishop of Albano, Italy, said Sunday the broad geographic distribution of the advisers was aimed at “enriching and amplifying the forms of communion in the highest echelons of the church institutions.”

Semeraro worked with Bergoglio during a 2001 meeting of the world’s bishops which Bergoglio chaired. In an indication of their close ties, Semeraro was one of the first people Francis received in private audience after his election, meeting with the new pope on the same day as the head of the Jesuit order, the Argentine president and the Vatican secretary of state.