The Christian laity is called to the ministry of evangelization in the Church and for the Church. In this work, basic ecclesial communities play an important role, because they are forming disciples of Christ and preparing them to bear testimony to the Gos-pel in the world. The communities have been initiated in the Church of South America and are centres of evangelization as a true expression of ecclesial communion (ChL no. 26). They also express the preferential option of the Church for the poor, because they are often created by people deprived of fair access to material goods and live on the margins of society. In the activities of basic ecclesial communities, the poor evan-gelize themselves first, feeding on the Word of God, to make it a source of inspiration for life and action. At that time, the poor are becoming subjects of evangelization, when they recognize the proclamation of the Good News of salvation as their task, not only with words but also through the testimony of life. The transmission of the Gospel occurs in interpersonal encounters in which the attitude of believers in Christ urges people to adopt Christian values and imbue in them the culture created by them.