Ordination is a religious, liturgical act which consecrates, blesses and sacramentalizes persons into the order of bishops, priests or deacons.
Orders is rooted in the mission and ministry of Jesus Christ; it enables the church to continue the mission and ministry of Jesus through the power of the Holy Spirit until the end of time.
The ministerial priest, by the sacred power that he has, forms and rules the priestly people; in the person of Christ he effects the Eucharistic sacrifice and offers it to God in the name of all the people. The faithful indeed, by virtue of their royal priesthood, participate in the offering of the Eucharist. They exercise that priesthood, too, by the reception of the sacraments, prayer and thanksgiving the witness of a holy life, abnegation and active charity. (Catechism of the Catholic Church #1546-47).
Sacrament of orders is essential and necessary so that all the baptized can participate in the ministry of Christ.
Celebrating the sacrament of orders has it emphasis on ministry and service to the community of faith; the needs of the Church but must also move the entire church to serve the needs of the world.