“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 (Bishop), Presbyterate (Priest), and Diaconate (Deacon).”

(CCC 1536, see also Philippians 1:1, 1 Timothy 3:8-13, 4:14, 2 Timothy 1:6, Titus 1:5, Acts 20:28, 14:23)