Jesus Christ is the Savior of the world, and He has entrusted the fullness of the Christian faith to the Catholic Church. Catholic Christians, therefore, have the obligation to share that fullness with all people throughout the whole world. The Vatican II Fathers addressed this responsibility for missionary activity in Ad Gentes Divinitus, or Decree on the Church's Missionary Activity.
Here is a sample of the topics and ideas you'll find in the first half of Ad Gentes Divinitus.
* Because the Catholic Church is “the universal sacrament of salvation,” she is “divinely sent” to preach the Gospel to the whole world. This is part of her nature.
* The goal of missionary activity is to “save and renew every creature” that all may be “restored in Christ” and be one family of God.
* All the faithful are obliged to spread the Kingdom of God everywhere.
Chapter I – Doctrinal Principles
* The Church is missionary by nature because she shares in the mission of Jesus Christ and the Holy Spirit, according to the Father's plan.
* God created and called a people who share in His life and live in community with each other.
* Jesus Christ is the “true Mediator” between God and humanity. He emptied Himself in the Incarnation and took on human nature so that He might restore humanity and raise it up to share in the divine nature.
* Jesus Christ and His salvation “must be proclaimed and spread to the ends of the earth.”
* The Holy Spirit is the soul of the Church. The Spirit accompanies and directs all apostolic action.
* Jesus gave His apostles the “Great Commission” when He sent them out to the whole world to preach the Gospel and baptize in the Name of the Father, the Son, and the Holy Spirit.
* The Church continues to carry out the “obligation to proclaim the faith and salvation which comes from Christ.”
* Through missionary activity the Church becomes fully present that she may lead all people to
faith, freedom and peace in Christ” through her life, teaching, sacraments, and other means of grace. In this way, she opens up for all people “a free and sure path to full participation in the mystery of Christ.”
* The missionary task is always the same but is carried out differently according to time, place, and circumstances. Missionary work usually involves “slow stages” and gradual progress.
* The goal of missionary activity, along with spreading the saving Word of God, is planting indigenous particular churches throughout the world.
* The “principal instrument” of missionary activity is “the preaching of the Gospel of Jesus Christ.” This preaching leads to baptism, which joins people to the Church that they might be further “nourished by the word of God and the Eucharist.”
* The missionary activity that flows from the Church's nature “extends the saving faith of the Church”; “expands and perfects its catholic unity; “is sustained by its apostolicity”; “activates the collegiate sense of its hierarchy”; and “bears witness to its sanctity.”
* Efforts to spread the Gospel are harmed by the disunity of Christians, who must strive “to come together in one flock” and “bear unanimous witness to Christ.”
* God wills that every person know Jesus Christ and be baptized. Faith, baptism, and the Church are necessary. Therefore, missionary activity is necessary.
* Love propels members of the Church to share the spiritual goods they have with all other people for the glory of God and the realization of His plan that all might be one family.
* All people have a longing for God built into their very nature. “In manifesting Christ, the Church reveals to men their true situation and calling” as well as their need for salvation.
* “Elements of truth and grace” are found among non-Christian people. Missionary activity purifies and elevates these elements and “restores them to Christ their source.”
Chapter II – Missionary Work
* There is still much missionary work to be done, and the Church must implant herself among many different groups of people in imitation of the Incarnate Christ, who “committed Himself to the particular social and cultural circumstances” of the people among whom He lived.
Article 1: Christian Witness
* All Christians must witness to their faith in life and word and show that they are new people in Christ through baptism and the power of the Holy Spirit.
* Witness must be founded on love and respect and promoted through contact, dialogue, and mutual knowledge.
* Christians should learn to see the seeds of the Word in the cultures and practices of non-Christians and help these seeds grow through the Gospel.
* The Church stands in solidarity with all people, suffering with them, sharing in their joys and sorrows, and entering into dialogue with them.
* Catholics should collaborate with other Christians and even non-Christians on social and educational projects in mission areas in order to serve both the material and spiritual needs of the residents as well as to promote unity and human dignity and to shine the light of Christ.
Article 2: Preaching the Gospel and Assembling the People of God
* God invites all people to “establish a personal relationship with Him in Christ.” To do this, they must first hear the Gospel and be touched by divine grace. They grow in their relationship through a lifelong spiritual journey.
* After their initial conversion, new believers enter the catechumenate, in which they are formed in the entire Christian life and are already joined to the Body of Christ. They must embrace this stage and their baptism with freedom and pure motives.
Article 3: Forming the Christian Community
* Missionaries “should raise up communities of the faithful” (i.e., particular churches) that they may participate in the “priestly, prophetic and royal offices” of Christ and be a “sign of God's presence in the world.”
* Each community should be “deeply rooted” in its people and cultural riches.
* Lay people play an especially important role in these young churches, for they are the “leaven animating and directing the temporal order from within.”
* Native clergy are key to the strength and stability of young churches, and vocations must be encouraged. Native priests should receive careful doctrinal, pastoral, and spiritual formation. They should also be well-versed in the conditions and culture of their own people.
* Well-trained catechists are extremely important in new communities, for they are co-workers with the priests who help spread the Word of God.
* Religious communities, both active and contemplative, should be founded in new churches.
Chapter III – Particular Churches
* Faith, charity, liturgy, catechesis, and true Christian living must be especially fostered in young churches.
* Bishops and priests should stress that young churches are part of the universal Church and must embrace the Catholic tradition even as they contribute their own riches to the universal Church.
* The local Church is a sign of Christ and represents the universal Church.
* Bishops, priests, religious, and lay people all have important roles to play in establishing and strengthening new particular churches.
* As soon as possible, young churches should participate in missionary activities to help spread the universal Church throughout the world.
* Lay people in young churches work alongside clergy and religious to witness to Christ in word and deed in their families, social groups, and professions. They “transform and permeate” society with the light of Christ as well as purify, guard, and develop their culture.
* Particular churches should “borrow from the customs, traditions, wisdom, teaching, arts and sciences of their people everything which could be used to praise the glory of the Creator, manifest the grace of the Saviour, or contribute to the right ordering of Christian life.”
* Culture is taken up into Christian life and “illumined by the light of the Gospel.”
The full text of Ad Gentes Divinitus is available online at the Vatican website.