The whole Church is a priestly people. Through Baptism all the faithful share in the priesthood of Christ. This participation is called the "common priesthood of the faithful." Based on this common priesthood and ordered to its service, there exists another participation in the mission of Christ: the ministry conferred by the sacrament of Holy Orders, where the task is to serve in the name and in the person of Christ the Head in the midst of the community.
(Catechism of the Catholic Church, #1591)

Blessed Pope John Paul II wrote of Holy Orders and the Priesthood in Pastores Dabo Vobis:

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.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, 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.


"What is the essence of the priesthood? The Epistles to the Hebrews gives us a celebrated definition. 'Every high-preist taken from among men is ordained for men in the things that appertain to God, that He may offer up gifts and sacrifices for sins (Hebrews 5:1)'. The priest is the mediator who offers to God oblations and sacrifices in the name of the people. In return God chooses the priest to communicate to men His gifts of grace, of mercy, and of pardon. The special excellence of the priesthood springs from this mediation". (Blessed Marmion Columba. Christ the Ideal of the Priest. Ignatius Press: San Francisco; 2005, 22-23).