The Second Vatican Council on the Ministry and Life of Priests
"Through the ministry of the priests, the spiritual sacrifice of the faithful is made perfect in union with the sacrifice of Christ. He is the only mediator who in the name of the whole Church is offered sacramentally in the Eucharist and in an unbloody manner until the Lord himself comes. The ministry of priests is directed to this goal and is perfected in it. Their ministry, which begins with the evangelical proclamation, derives its power and force from the sacrifice of Christ. Its aim is that "the entire commonwealth of the redeemed and the society of the saints be offered to God through the High Priest who offered himself also for us in his passion that we might be the body of so great a Head." The purpose, therefore, which priests pursue in their ministry and by their life is to procure the glory of God the Father in Christ. That glory consists in this-that men working freely and with a grateful spirit receive the work of God made perfect in Christ and then manifest it in their whole lives. Hence, priests, while engaging in prayer and adoration, or preaching the word, or offering the Eucharistic Sacrifice and administering the other sacraments, or performing other works of the ministry for men, devote all this energy to the increase of the glory of God and to man's progress in the divine life." (Presbyterorum Ordinis 2)
The Ministry of Priests