5 God, who alone is holy and who alone bestows holiness, willed to take as his companions and helpers men who would humbly dedicate themselves to the work of sanctification. Hence, through the ministry of the bishop, God consecrates priests, that being made sharers by special title in the priesthood of Christ, they might act as his ministers in performing sacred functions. In the liturgy they continue to carry on his priestly office by the action of his Spirit. By Baptism men are truly brought into the People of God; by the sacrament of Penance sinners are reconciled to God and his Church; by the Anointing of the Sick, the ill are given solace; and especially by the celebration of Mass they offer sacramentally the Sacrifice of Christ. In administering all sacraments, as St. Ignatius Martyr has borne witness from the early days of the Church, priests by various titles are bound together hierarchically with the bishop. And so in a certain way they make him present in every congregation. The other sacraments, as well as with every ministry of the Church and every work of the apostolate, are tied together with the Eucharist and are directed toward it. The Most Blessed Eucharist contains the entire spiritual boon of the Church, that is, Christ himself, our Pasch and Living Bread, by the action of the Holy Spirit through his very flesh vital and vitalizing, giving life to men who are thus invited and encouraged to offer themselves, their labors and all created things, together with him. In this light, the Eucharist shows itself as the source and the apex of the whole work of preaching the Gospel. Those under instruction are introduced by stages to a sharing in the Eucharist, and the faithful, already marked with the seal of Baptism and Confirmation, are through the reception of the Eucharist fully joined to the Body of Christ. Thus the Eucharistic Action, over which the priest presides, is the very heart of the congregation. So priests must instruct their people to offer to God the Father the Divine Victim in the Sacrifice of the Mass, and to join to it the offering of their own lives. In the spirit of Christ the Shepherd, they must prompt their people to confess their sins with a contrite heart in the sacrament of Penance, so that, mindful of his words "Repent for the kingdom of God is at hand" (Mt 4:17), they are drawn closer to the Lord more and more each day. Priests likewise must instruct their people to participate in the celebrations of the sacred liturgy in such a way that they become proficient in genuine prayer. They must coax their people on to an ever more perfect and constant spirit of prayer for every grace and need. They must gently persuade everyone to the fulfillment of the duties of his state of life, and to greater progress in responding in a sensible way to the evangelical counsels. Finally, they must train the faithful to sing hymns and spiritual songs in their hearts to the Lord, always giving thanks to God the Father for all things in the name of our Lord Jesus Christ. Priests themselves extend to the other hours of the day the praise and thanksgiving of the Eucharistic celebration in praying the Divine Office, offered in the name of the Church for all the people entrusted to their care, and indeed for the whole world. The house of prayer in which the Most Holy Eucharist is celebrated and reserved, where the faithful gather and where the presence of the Son of God, our Savior, offered for us on the altar of sacrifice bestows strength and blessings on the faithful, must be spotless and suitable for prayer and sacred functions. There pastors and the faithful are called to acknowledge with grateful heart the gift of him, Who through his humanity constantly pours divine life into the members of his Body. Let priests take care so to foster a knowledge of and facility in the liturgy, that by their own liturgical ministry Christian communities entrusted to their care may ever more perfectly give praise to God, the Father, and Son, and Holy Spirit.
Source: Presbyterorum Ordinis (Vatican.va)