17. By its very nature, the ordained ministry can be carried out only to the extent that the priest is united to Christ through sacramental participation in the priestly order, and thus to the extent that he is in hierarchical communion with his own bishop. The ordained ministry has a radical "communitarian form" and can only be carried out as "a collective work."( ³⁰) The Council dealt extensively with this communal aspect of the nature of the priesthood, (³¹) examining in succession the relationship of the priest with his own bishop, with other priests and with the lay faithful.

The ministry of priests is above all communion and a responsible and necessary cooperation with the bishop's ministry, in concern for the universal Church and for the individual particular churches, for whose service they form with the bishop a single presbyterate.

Each priest, whether diocesan or religious, is united to the other members of this presbyterate on the basis of the sacrament of holy orders and by particular bonds of apostolic charity, ministry and fraternity All priests in fact, whether diocesan or religious, share in the one priesthood of Christ the head and shepherd; "they work for the same cause, namely, the building up of the body of Christ, which demands a variety of functions and new adaptations, especially at the present time,"( ³²) and is enriched down the centuries by ever new charisms.

Finally, because their role and task within the Church do not replace but promote the baptismal priesthood of the entire People of God, leading it to its full ecclesial realization, priests have a positive and helping relationship to the laity. Priests are there to serve the faith, hope and charity of the laity. They recognize and uphold, as brothers and friends, the dignity of the laity as children of God and help them to exercise fully their specific role in the overall context of the Church's mission.( ³³) The ministerial priesthood conferred by the sacrament of holy orders and the common or "royal" priesthood of the faithful, which differ essentially and not only in degree,( ³⁴) are ordered one to the other -- for each in its own way derives from the one priesthood of Christ. Indeed, the ministerial priesthood does not of itself signify a greater degree of holiness with regard to the common priesthood of the faithful; through it Christ gives to priests, in the Spirit, a particular gift so that they can help the People of God to exercise faithfully and fully the common priesthood which it has received.( ³⁵)