St. Paul said to his disciple Timothy, “I remind you to rekindle the gift of God that is within you through the laying on of my hands” (2 Timothy 1:6) and “If any one aspires to the office of bishop, he desires a noble task.” (1 Timothy 3:1) To Titus he said, “This is why I left you in Crete, that you amend what was defective, and appoint presbyters in every town, as I directed you.” (Titus 1:5).
The Catechism of the Catholic Church States: “Holy Orders is the sacrament through which the mission entrsuted 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 (bishops), presbyterate (priests), and diaconate (deacons).”