The Church on Mission
From the Catechism of the Catholic Church, Simplified
Sent to the Whole World (849-850)
Because of Jesus' command to make disciples of all nations, the Church has been divinely sent as "the universal sacrament of salvation" and must preach the Gospel to everyone.
The Church is missionary because (according to the Father's plan) she has her origin in the mission of Son and Spirit. The Church exists to bring all men into the communion of the Father, Son, and Spirit.
To Save All (851)
God "desires all men to be saved and to come to a knowledge of the truth (1 Tim 2:4). Therefore, the Church must go out to those who are seeking God and bring them the Gospel. The Church must be missionary because she believes in God's universal plan.
Led by the Spirit (852)
The Holy Spirit is the "protagonist" who guides the Church on her missionary paths leading her to follow Christ's path of service and self-sacrifice. "The blood of martyrs is the seed of the Church" (Tertullian).
Failures and Patience (853-854)
The Church recognizes the great discrepancy between her message and her human weaknesses. Only by walking the way of the cross can she extend Christ's reign.
This missionary endeavor begins by proclaiming the Gospel to unbelievers, then by establishing communities of believers, and finally by founding a local church. This involves a process of enculturation, so that the Gospel takes flesh in each culture. Only by degrees can the Church penetrate the culture.
The Obstacle of Divisions (855)
The missionary endeavor stimulates efforts to Christian unity because the divisions among Christian churches is a serious obstacle to missionary activity. Because of division, the Church cannot display its full Catholic unity.
The Truths in Each Culture (856)
The missionary task must appreciate those elements of truth which God has already given to the unbelievers. Proclaiming the Good News should raise up this truth, while purifying it from error and evil.