"And he gave some as apostles, others as prophets, others as evangelists, others as pastors and teachers, to equip the holy ones for the work of ministry, for building up the body of Christ....Rather, living the truth in love, we should grow in every way into him who is the head, Christ, from whom the whole body, joined and held together by every supporting ligament, with the proper functioning of each part, brings about the body's growth and builds itself up in love."   (Eph. 4:11-12, 15,16)
 

ABOUT THE SACRAMENT OF HOLY ORDERS

The Sacrament of Holy Orders is also called Ordination.  It is the sacrament by which a Christian man becomes a bishop, priest, or deacon.  The matter of the sacrament is the laying on of hands; the form is the prayer said at Ordination.

Bishops belong to the college of bishops and serves as the visible head or pastor of the local church entrusted to his care.  As a college, the bishops have care and concern for the mission of all the churches in union with and under the authority of the Pope.

Priests are called to love the Church as a husband loves his wife, and to renounce marriage and family in order to devote themselves fully to the service of God and his people.  This is one reason why the Church insists upon the celibacy of priests.
Priests are able to perform six sacraments: Baptism, the Eucharist, Confession, Marriage, Anointing of the Sick and Confimation (when given a dispensation to do so by their bishop).  

Deacons,  whose role is primarily to assist the priest, may be married men.  However, once a single man is ordained a deacon, he cannot marry.  Likewise, if a married deacon loses his wife, he may not remarry except under certain approved conditions.  Deacons are able to perform two sacraments: Baptism and Marriage.
 

In the Sacrament of Holy Orders, there are three degrees or "orders": bishop, priest, and deacon.  The rite of ordination is the sacramental act that makes this possible.  Ordination "confers a gift of the Holy spirit that permits the exercise of a 'sacred power'... which can come only from Christ himself through the Church."
-CCC, no. 1538