Why do Catholics have Bishops?
St. Timothy in Ephesus and St. Titus in Crete each received instructions from the apostle Paul about the qualifications for a bishop (see 1 Tm 3:1-7; Ti 1:7-9). This "noble officer was to "teach" and to "manage" the affairs of the Church in each locale. (The Greek word for bishop, episkopos, literally means "overseer.") How did the office of bishop come about?
Our Lord appointed the apostles to teach and govern the Church (see Mt 28:16-20). Since the place of Judas had been vacated by the traitor's suicide, a successor was appointed by the other apostles to fill his "office" (see Acts 1:20)--literally, his "episcopacy" or "bishopric" (Greek, episkopen). The first apostles, then, were bishops, as were their appointed successors (see "Why do Catholics believe in Apostolic Succession?").
In referring to ordained Church leaders, biblical writers do not always distinguish clearly between bishops/overseers and presbyters/elders/priests. St. Luke, for example, refers to the leaders of the Church at Ephesus first as "presbyters" and then as "overseers" (see Acts 20:17, 28). But those distinctions were clarified within a generation after the apostles, as evidenced by the writings of their immediate successors, such as St. Ignatius, bishop of Antioch.
Since the beginning, then the Catholic Church as been governed by bishops, maintaining an episcopal form of government. Protestant denominations have experimented with a variety of alternative structures, such as congregational (governed by vote of the entire congregation and presbyterian (governed by a system of courts composed of elders). But having received her episcopal structure from Christ, through his apostles, the Catholic Church has preserved it for two thousand years as a divine mandate--though with some historical variations in the methods of appointment and the exercise of the office.
The bishops serve as shepherds of God's flock (see 1 Pt 5:1-4). In governing the Church, they are to imitate the pastoral care of Jesus himself for his people. He is the chief "shepherd and guardian (episkipos) of...souls" (1 Pt 2:25).
Other related scriptures: Jer 23:4; Mt 9:36; Mk 6:34; Phil 1:1; Heb 13:20.
Catechism of the Catholic Church: 3; 77; 815-816; 830; 833; 873; 857-864; 869; 873-896; 919; 935-939; 981; 1087; 1120-1121; 1142; 1369; 1483; 1549; 1560-1561; 1575-1577; 1593-1596; 1600; 1673.
*Quoted from The New Catholic Answer Bible. Wichita, Kansas, Fireside Catholic Publishing, 2005. www.firesidecatholic.com
Additional insights at: www.catholic.com