15 The Holy Spirit, who calls all men to Christ by the seeds of the Lord and by the preaching of the Gospel, stirs up in their: hearts a submission to the faith Who in the womb of the baptismal font, He begets to a new life those who believe in Christ, He gathers them into the one People of God which is "a chosen race, a royal priesthood, a holy nation, a purchased people" (1 Peter 2:9). Therefore, let the missionaries, God's coworkers, ( cf. 1 Cor. 3:9), raise up congregations of the faithful such that, walking worthy of the vocation to which they have been called (cf. Eph. 4:1), they may exercise the priestly, prophetic, and royal office which God has entrusted to them. In this way, the Christian community will be a sign of God's presence in the world: for by reason of the eucharistic sacrifice, this community is ceaselessly on the way with Christ to the Father; carefully nourished on the word of God it bears witness to Christ; and finally, it walks in charity and is fervent with the apostolic spirit. The Christian community should from the very start be so formed that it call provide nor its necessities insofar as this is possible. This congregation of the faithful, endowed with the riches of its own nation's culture, should be deeply rooted in the people. Let families flourish which are imbued with the spirit of the Gospel and let them be assisted by good schools; let associations and groups be organized by means of which the lay apostolate will be able to permeate the whole of society with the spirit of the Gospel. Lastly, let charity shine out between Catholics of different rites. The ecumenical spirit should be nurtured in the neophytes, who should take into account that the brethren who believe in Christ are Christ's disciples, reborn in baptism, sharers with the People of God in very many good things. Insofar as religious conditions allow, ecumenical activity - should be furthered in such a way that, excluding any appearance of indifference or confusion on the one hand, or of unhealthy rivalry on the other, Catholics should cooperate in a brotherly spirit with their separated brethren, among to the norms of the Decree on Ecumenism, making before the nations a common profession of faith, insofar as their beliefs are common, in God and in Jesus Christ, and cooperating in social and in technical projects as well as in cultural and religious ones. Let them cooperate especially for the sake of Christ, their common Lord: let His Name be the bond that unites them! This cooperation should be undertaken not only among private persons, but also, subject to approval by the local Ordinary, among churches or ecclesial communities and their works. The Christian faithful gathered together out of all nations into the Church "are not marked off from the rest of men by their government, nor by their language, nor by their political institutions," and so they should live for God and Christ in a respectable way of their own national life. As good citizens, they should be true and effective patriots, all together avoiding racial prejudice and hypernationalism, and should foster a universal love for man. To obtain all these things, the most important and therefore worthy of special attention are the Christian laity: namely, those who have been incorporated into Christ and live in the world. For it is up to them, imbued with the spirit of Christ, to be a leaven working on the temporal order from within, to dispose it always in accordance with Christ. But it is not enough that the Christian people be present and be organized in a given nation, nor is it enough to carry out an apostolate by way of example. They are organized for this purpose, they are present for this, to announce Christ to their non - Christian fellow - citizens by word and example, and to aid them toward the full reception of Christ. Now, in order to plant the Church and to make the Christian community grow, various ministries are needed, which are raised up by divine calling from the midst of the faithful congregation, and are to be carefully fostered and tended to by all. Among these are the offices of priests, of deacons, and of catechists, and Catholic action. Religious men and women likewise, by their prayers and by their active work, play an indispensable role in rooting and strengthening the Kingdom of Christ in souls, and in causing it to be spread.
Source: Ad Gentes (Vatican.va)