"Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in the Church until the end of time: thus it is the sacrament of apostolic ministry. It includes three degrees: episcopate, presbyterate, and diaconate." 
Catechism of the Catholic Church, 1536

Houston Vocations is a website produced by the Archdiocese of Galveston-Houston to help men and women better understand how understanding your vocation can be life changing.