Missiology March 26, 2023


“Go, therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit, teaching them to observe all that I have commanded you.” – Matthew 28:19-20.

Every person in the Bible who encounters God is sent on a mission. From Abraham and Moses to Peter and Paul, to encounter God is to be tasked with doing His work. This holds not just at the level of the individual, but at the level of the Church that God created.

In this paper, I will provide an introduction to missiology. I will begin by defining missiology and examine some of the essential documents that help provide insight into understanding missiology in the Catholic Church.

Mission And The Bible

Missiology is that aspect of theology that studies the principles and practice of the missions. As such, missiology can be said to be the science of evangelization and catechesis in regions and among people where the Church is being established. It is acting upon the Great Commission issued by Christ in Matthew 28:19-20. Two examples should suffice to show a missiology motif in the Bible. 

In the Acts of the Apostles, Phillip the Apostle is tasked with traveling to Samaria to preach. (See Acts 8:5). We also read of Paul acting on Jesus’ words. After his conversion, Paul became one of the Church’s great evangelists, preaching the Gospel despite being beaten and imprisoned at various times. (See Chapter 28 of the Acts of the Apostles).

In examining the Catholic Church’s history, several documents are foundational to the Church’s missionary work. There are three documents issued prior to World War Two that I would like to examine.

The first document was an encyclical letter written by Pope Gregory called Prope Nosti – On the Propagation of the Faith. Pope Gregory XVI was an enthusiastic supporter of Catholic missions, both among priests and bishops as well as lay people. He also encouraged female missionary religious orders. A key component of Prope Nosti was to remind and encourage bishops to propagate the Catholic faith beyond their dioceses to the whole world. The encyclical further seeks to facilitate the use of the laity in engaging in missionary work.

The second document of significance in missiology was an apostolic letter authored by Pope Benedict XV titled Maximum Illud – On the Propagation of the Faith Throughout the World. Maximum Illud was primarily concerned with the expansion of Catholic missionary work in the wake of World War I. Pope Benedict XV expressed the importance of bishops and the superiors in charge of missions to develop a program to train local clergy. The Pope emphasized the necessity of proper preparation for work in foreign cultures and acquiring language skills. The letter concludes by pointing to several organizations which organize and supervise mission activities within the Catholic Church.

The third document of significance to the missions of the Church issued prior to World War Two was Pope Pius XI’s Revrum Ecclesiae – On Promoting the Sacred Missions. Revrum Ecclesiae was primarily concerned with the founding, solidification, and independence of the new churches. The encyclical sought the creation and development of an autochthonous clergy and orders that would correspond to the expectations and interests of the faithful as well as to the regional conditions and circumstances. Additionally, Revrum Ecclesiae sought a contemplative monastic system and autochthonous catechists and laymen whose careful training would be invaluable for the future of the Church.

Following World War Two, the Catholic Church issued numerous documents related to its missionary work. To be as concise as possible, I will reference only three documents that are of great importance to missiology.

On the twenty-fifth anniversary of Revrum Ecclesiae, Pope Pius XII issued Evangelii Praecones – On Promoting Catholic Missions. The encyclical stressed the importance of establishing the Catholic Church among people not yet exposed to Christianity. To facilitate this work, Pope Pius XII emphasized the need for Church leaders to be native to the people that the Church sought to evangelize. The encyclical also emphasized that missionaries must be respectful of the cultures in which they were bringing the Gospel message. It was important that Catholic missionaries “Let not the Gospel on being introduced into any new land destroy or extinguish whatever its people possess that is naturally good, just or beautiful. For the Church, when she calls people to a higher culture and a better way of life, under the inspiration of the Christian religion, does not act like one who recklessly cuts down and uproots a thriving forest. No, she grafts a good scion upon the wild stock that it may bear a crop of more delicious fruit.”

The second document is a product of the Second Vatican Council. It is called Ad Gentes – Decree on the Missionary Activity of the Church. Ad Gentes sought to establish evangelization as one of the fundamental missions of the Catholic Church. The decree underscores the connection between evangelization and charity for the less fortunate. Ad Gentes also calls for forming strong lay groups and relations with other Christians. Lastly, Ad Gentes lays out guidelines for the training and actions of the missionaries.

The last document I would like to reference is an apostolic exhortation from Pope Paul VI called Evangelii Nuntiandi – Evangelization in the Modern World. This exhortation updates the state of the Church ten years removed from the Second Vatican Council. Evangelii Nuntiandi sought to define evangelization within the context of the modern world. The Pope clarifies the importance of evangelization as fundamental to the human desire for truth. The exhortation then points out that part of evangelizing entails Catholics living in such a way as to be witnesses to the Gospel message.

Additionally, Evangelii Nuntiandi enumerates methods of evangelizing. In addition to being witnesses to the truth, Catholic missionaries must preach and provide means of proper catechesis. Finally, Evangelii Nuntiandi points out the importance of personal contact, mass media, and the sacraments for evangelizing.


The Catholic Church has been tasked with, among other things, making disciples of all people. The Great Commission provides the basis for the Church’s evangelization. Evangelization requires that the Church develop and maintain missionaries throughout the world.

In this paper, I have sought to explain missiology as the science of evangelization and catechesis responsible for spreading the Gospel message.


About David Schloss
I am a convert from Judaism to Catholicism with a background in philosophy. It is my hope that my articles can help further the understanding of the Catholic faith while making clear that faith is not the absence of reason, but its fulfillment. Fides et ratio. You can read more about the author here.

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