When Paul lists the gifted men given to the church in Ephesians 4:11 he says that Jesus “gave some as apostles, and some as prophets, and some as evangelists, and some as pastors and teachers.” The last group “pastors and teachers” is one office not two. The word “pastors” is the word poimen, which means “shepherd.” This word “emphasizes the care, protection, and leadership of the man of God for his flock” (MacArthur). The word “and” or kai which appears between pastor and teacher can also be translated, “that is” or “in particular.” It “indicates that the shepherds and teachers are viewed as one common group, i.e., ‘teaching shepherds’” (Fritz Rienecker, The Linguistic Key to the Greek NT, p.531). Kenneth Wuest says, “The words "pastors" and "teachers" are in a construction called Granvill Sharp's rule which indicates that they refer to one individual. The one who shepherds God's flock is also a teacher of the Word, having both the gifts of shepherding and teaching the flock. God's ideal pastor is one who engages in a didactic ministry, feeding the saints on expository preaching, giving them the rich food of the Word” (Word Studies in the Greek New Testament). John MacArthur adds: “The teaching shepherd’s main task is to protect the flock. That’s what shepherding is – protecting from both dangerous places and enemies. The pastor-teacher does this by building safeguards, teaching the truth, and helping those who may be stumbling into sin. He not only preserves them, but strengthens and encourages them. Jesus, of course, is the great shepherd. He loves His flock. He builds His church. He does so by giving the Body gifted men – evangelists and pastor-teachers” (John MacArthur and Fred Barshaw, Leading the Flock, p.11).
Some of their duties are: Teach the Word of God (1 Tim.3:2), Give oversight to the church (Acts 20:28), and model godliness (1 Peter 5).