Pastors are to act like shepherds by caring for the flock, and this care includes teaching. The New Testament typically uses the words "bishops" () and "presbyter" (1 Peter 5:1) to indicate the ordained leadership in early Christianity. Likewise, Peter instructs these particular servants to "act like shepherds" as they "oversee" the flock of God (1 Pet. 5:2). The words "bishop" and "presbyter" were sometimes used in an interchangeable way, such as in Titus 1:5-6. However, there is ongoing dispute between branches of Christianity over whether there are two ordained classes (presbyters and deacons) or three (bishops, priests, and deacons). In the Catholic Church, Orthodox Church, and Oriental Orthodox Church bishops, priests, and deacons are those who have been ordained with apostolic lineage. In most Protestant denominations and non-denominational churches, in contrast, bishops are rejected, as well as the doctrine of apostolic succession.