Pope Francis has told Catholic priests to leave their comfort zone and get out among people on the margins of society or else risk becoming "abstract ideologists".
Civilta Cattolica, a Jesuit journal, has published text of a meeting the pontiff had in late November with the heads of orders of priests from around the world.
Pope Francis said priests had to have real contact with the poor and the marginalised.
"This is really very important to me: the need to become acquainted with reality by experience, to spend time walking on the periphery in order really to become acquainted with the reality and life-experiences of people," he told them.
"If this does not happen we then run the risk of being abstract ideologists or fundamentalists, which is not healthy."
Since his election, Francis has been urging priests, nuns and bishops to think less about their careers in the church and to listen more to the needs of ordinary Catholics, especially the poor.
Francis was known as a "slum bishop" in Argentina because of his work among the poor.
His first visits after moving to the Vatican were to a jail for juveniles and to the southern Italian island of Lampedusa to pay tribute to impoverished immigrants who have died trying to get to Europe.
During the meeting with the religious leaders, Francis said men should not enter the priesthood to seek a comfortable life or to rise up the clerical career ladder.
"The ghost to fight against is the image of religious life understood as an escape or hiding place in face of an 'external' difficult and complex world," he told them.
Francis has said several times since his election that he feels the Vatican is too self-centred and needs to change.