VATICAN CITY (CNS) -- To be able to fulfill its mission of preaching the Gospel, the church must first evangelize itself, Pope Francis said.

"Mission, in fact, is a force capable of transforming the church within itself even before it does so in the life of peoples and cultures," the pope told participants of the plenary assembly of the Congregation for the Evangelization of Peoples.

The plenary assembly, which commemorated the 50th anniversary of "Ad Gentes," the Second Vatican Council's decree on the church's missionary activity, focused on missionary awareness and the work being done in regions of the world that have been evangelized most recently.

Recalling his visit to Africa Nov. 25-30, the pope said that he experienced "firsthand the spiritual and pastoral dynamism of so many young churches in that continent, as well as the harsh difficulties lived by most of the population."

"I have seen that where there are needs, there is almost always a presence of the church ready to heal the wounds of the neediest in whom they recognize the wounded and crucified body of our Lord Jesus," he said.

The pope said that by its very nature, the church evangelizes; however, it must always begin by evangelizing itself in order to have the "grace of the Holy Spirit" as its foundation and safeguard its "apostolic freshness and urgency."

In this way, he said, "the Holy Spirit transforms those who are believers by habit only into disciples (and) alienated disciples into missionaries, pulling them out of their fears and closures and sending them in every direction, to the ends of the world."

Pope Francis said that in evangelizing young churches, missionaries are called to a step-by-step, "kerygmatic approach to faith" and that missionaries must learn to listen to the cry of the poor and the marginalized.

"Let us pray and work so that the church is always more along the lines of the Acts of the Apostles," which describes the lifestyle and missionary enthusiasm of the first Christians, he said. "Let us be inspired by the power of the Gospel and the Holy Spirit."