In the Sacrament of Holy Orders, a man is fitted for service to the People of God as a Bishop, a priest, or a deacon. By the grace of this Sacrament, he is sent by God to be the “means by which Christ unceasingly builds up and leads his Church.” (Catechism of the Catholic Church, 1547)
The Sacrament of Holy Orders is handed on by the ancient symbol of the laying on of hands. In the Rite of Ordination, the bishop places his hands on the head of the man to be ordained (in the case of the ordination of a bishop, three bishops do this). This gesture carries with it the natural meaning of “I choose this one.” Thus, in an ordination, what we see with our physical eyes is a bishop choosing someone for something. But with the eyes of faith, we see God Himself choosing and fitting a man for service to His people, to build them up more and more perfectly as the Body of Christ in the world. And ever after, when we see the bishop, or the priest, or the deacon, through the eyes of faith we can see Christ among His people as their Servant, their Teacher, and their Head. This the ordained do by proclaiming and preaching the Word, by celebrating the Sacraments, by teaching the faith, and by being living examples to all. The Sacrament of Holy Orders, then, is the Sacrament by which a man is essentially configured to Christ in service to His holy people.