"The Christian faithful are those who, inasmuch as they have been incorporated in Christ through Baptism, have been constituted as the people of God; for this reason, since they have become sharers in Christ's priestly, prophetic, and royal office in their own manner, they are called to exercise the mission which God has entrusted to the Church to fulfill in the world, in accord with the condition proper to each one."

872 "In virtue of their rebirth in Christ there exists among all the Christian faithful a true equality with regard to dignity and the activity whereby all cooperate in the building up of the Body of Christ in accord with each one's own condition and function."

873 The very differences which the Lord has willed to put between the members of his body serve its unity and mission. For "in the Church there is diversity of ministry but unity of mission. To the apostles and their successors Christ has entrusted the office of teaching, sanctifying and governing in his name and by his power. But the laity are made to share in the priestly, prophetical, and kingly office of Christ; they have therefore, in the Church and in the world, their own assignment in the mission of the whole People of God." Finally, "from both groups [hierarchy and laity] there exist Christian faithful who are consecrated to God in their own special manner and serve the salvific mission of the Church through the profession of the evangelical counsels."

I. THE HIERARCHICAL CONSTITUTION OF THE CHURCH

Why the ecclesial ministry?

874 Christ is himself the source of ministry in the Church. He instituted the Church. He gave her authority and mission, orientation and goal:

In order to shepherd the People of God and to increase its numbers without cease, Christ the Lord set up in his Church a variety of offices which aim at the good of the whole body. The holders of office, who are invested with a sacred power, are, in fact, dedicated to promoting the interests of their brethren, so that all who belong to the People of God ... may attain to salvation.

875 "How are they to believe in him of whom they have never heard? And how are they to hear without a preacher? And how can men preach unless they are sent?" No one — no individual and no community — can proclaim the Gospel to himself: "Faith comes from what is heard." No one can give himself the mandate and the mission to proclaim the Gospel. The one sent by the Lord does not speak and act on his own authority, but by virtue of Christ's authority; not as a member of the community, but speaking to it in the name of Christ. No one can bestow grace on himself; it must be given and offered. This fact presupposes ministers of grace, authorized and empowered by Christ. From him, bishops and priests receive the mission and faculty ("the sacred power" to act in persona Christi Capitis; deacons receive the strength to serve the people of God in the diaconia of liturgy, word and charity, in communion with the bishop and his presbyterate. The ministry in which Christ's emissaries do and give by God's grace what they cannot do and give by their own powers, is called a "sacrament" by the Church's tradition. Indeed, the ministry of the Church is conferred by a special sacrament.

876 Intrinsically linked to the sacramental nature of ecclesial ministry is its character as service. Entirely dependent on Christ who gives mission and authority, ministers are truly "slaves of Christ," in the image of him who freely took "the form of a slave" for us. Because the word and grace of which they are ministers are not their own, but are given to them by Christ for the sake of others, they must freely become the slaves of all.

877 Likewise, it belongs to the sacramental nature of ecclesial ministry that it have a collegial character. In fact, from the beginning of his ministry, the Lord Jesus instituted the Twelve as "the seeds of the new Israel and the beginning of the sacred hierarchy." Chosen together, they were also sent out together, and their fraternal unity would be at the service of the fraternal communion of all the faithful: they would reflect and witness to the communion of the divine persons. For this reason every bishop exercises his ministry from within the episcopal college, in communion with the bishop of Rome, the successor of St. Peter and head of the college. So also priests exercise their ministry from within the presbyterium of the diocese, under the direction of their bishop.

878 Finally, it belongs to the sacramental nature of ecclesial ministry that it have a personal character. Although Christ's ministers act in communion with one another, they also always act in a personal way. Each one is called personally: "You, follow me" in order to be a personal witness within the common mission, to bear personal responsibility before him who gives the mission, acting "in his person" and for other persons: "I baptize you in the name of the Father and of the Son and of the Holy Spirit ..."; "I absolve you . ..."

879 Sacramental ministry in the Church, then, is a service exercised in the name of Christ. It has a personal character and a collegial form. This is evidenced by the bonds between the episcopal college and its head, the successor of St. Peter, and in the relationship between the bishop's pastoral responsibility for his particular church and the common solicitude of the episcopal college for the universal Church.