The Sacrament of Holy Orders is a Sacrament of Mission because it is given to build up Christ's body, the Church. As such it is a vocation, a calling given by God to live our Christian life by serving others in a particular way.
The call to Holy Orders may be a call to priesthood or to the diaconate. Both vocations are discerned initially by the individual and then definitively, after a period of prayer and preparation, by the Church. It is ultimately the Church, in the person of the bishop, who calls a man to serve as a priest or as a deacon.
The call to priesthood is a celibate vocation whereby a man makes himself totally available to proclaim God's Word, administer the Sacraments, and care for the people, wherever the Church may choose to send him.
The call to the diaconate is also given to married men who serve the local church as deacons usually attached to a specific parish. As well as proclaiming the Word, a permanent deacon also administers the Sacraments of Baptism and Marriage, and officiates at funeral services.
Anyone who thinks he may be called to priesthood or the diaconate is warmly encouraged to speak with their parish priest.