A footnote found in the TEV Bible at bible.org provides us with a nice summary of the passage under consideration:
"Some interpreters have understood the phrase pastors and teachers to refer to one and the same group. This would mean that all pastors are teachers and that all teachers are pastors. This position is often taken because it is recognized that both nouns (i.e., pastors and teachers) are governed by one article in Greek. But because the nouns are plural, it is extremely unlikely that they refer to the same group, but only that the author is linking them closely together. It is better to regard the pastors as a subset of teachers. In other words, all pastors are teachers, but not all teachers are pastors" (my emphasis).
Complicating things a bit is the office of bishop (alternately, elder or overseer) whom Peter called "shepherds of the flock" (1 Peter 5:2), since the norm for local churches in the first century seems to have been a plurality of bishops/elders/overseers/under-shepherds, with Christ as the Good Shepherd who gave His life for the sheep (see John 10: 11 and 14; Acts 20:17 and 28).
"For this reason I [Paul] left you in Crete, that you [Titus] would set in order what remains and appoint elders in every city as I directed you" (Titus 1:5 NAS).
Complicating things even further is that one of the qualifications to be a ruling elder is the ability to teach, or as a number of versions put it, "apt to teach." I like the use of the word apt, which in addition to meaning able also carries with it the concept of fitness to perform the task of teaching, particularly when false teaching threatens to spoil the unity within a local congregation (or even, perhaps, an entire denomination!). This verse implies, I believe, that an elder may not have the gift of teaching, but he or she does have sufficient biblical savvy (if I may put it that way) to recognize bad doctrine from good, and is able to confront and refute bad doctrine.
Another aspect of fitness is a biblical integrity and sincerity. God does not want hypocritical leaders in his church. A church's leaders must be above reproach (1 Timothy 3:2; 3:10; and Titus 1:6-7); if not, they are not fit (or apt) to teach. In other words, not every elder is necessarily gifted by the Holy Spirit to be a teacher to the body, but every elder needs to be fit to teach in two modes, if you will:
sound doctrine, which can be measured against apostolic teaching and doctrine which were once and for all delivered to the saints (see Jude 1:3b NASB Updated).
refutation, which uses apostolic teaching to confront false teachers and refute their false teaching, as Titus 1:9 makes clear:
". . . holding fast the faithful word which is in accordance with the teaching, so that . . . [an elder] will be able both to exhort in sound doctrine and to refute those who contradict."
Put differently, the elders in a local church are to be diligent in spotting and exposing a counterfeit faith, but they must also be diligent in studying the real faith, which is, interestingly, how Treasury Department investigators learn how to spot counterfeit money; namely, by studying the real thing!
Before positing a tentative answer to your question, we need to consider another wrinkle in the exercise of the "spirituals" (i.e., spiritual gifts) and the fulfillment of roles within a church or group of churches. Paul addresses that wrinkle in 1 Timothy 5:17-18:
"The elders who rule well are to be considered worthy of double honor , especially those who work hard at preaching and teaching. For the Scripture says, 'YOU SHALL NOT MUZZLE THE OX WHILE HE IS THRESHING," and 'The laborer is worthy of his wages.'"
Putting all the above information together, I suggest there are several kinds of servant-leaders in any given local church, or any group of local churches, no matter the size or how widely spread geographically they might be. (Remember, Titus was responsible for appointing elders in at least two or more churches--"in every city"--in Crete).
- elders/pastors/under-shepherds who serve a church or churches in a volunteer capacity and who support themselves with the income from "normal jobs," whatever those jobs may be. The day to day care of the church may be entrusted to another person who is called by God to serve fulltime, with the congregation providing for his support (and that of his family, if that pertains).
- elders/pastors/under-shepherds who serve as fulltime preachers and teachers within a church or churches and who deserve to be supported financially by their church or churches since they "work hard at preaching and teaching." I suggest this category of person is the equivalent of our modern-day vocational minister/pastor/priest/rector who is supported by his or her local church (or denomination) after being "ordained" for such a ministry. Usually, some sort of extensive education, training, and/or credentialing is required of fulltime vocational ministers of the word today.
- elders/pastors/under-shepherds who could be described as "tentmakers." They are servant-leaders who supplement their income with part-time (possibly fulltime) jobs or trades as needed (e.g., making and repairing tents, as the apostle Paul did, Acts 18:3). Like Paul, they may be sent forth by a church or denomination to be cross-cultural missionaries, for example, in the "field" to which they are called. Sometimes their denomination provides a salary, and sometimes these modern-day apostles may be required to raise their own support from a number of churches and individuals (e.g., family members and friends)
Putting all these seemingly disparate parts together, I think it is safe to conclude the following:
- a pastor/teacher is a gift from God to the church universal in whatever incarnation that church or para-church ministry might take:
- "And He [the resurrected Jesus] gave [to the church universal] some as apostles, and some as prophets, and some as evangelists, and some as pastors and teachers, for the equipping of the saints for the work of service, to the building up of the body of Christ; until we all attain to the unity of the faith, and of the knowledge of the Son of God, to a mature man, to the measure of the stature which belongs to the fullness of Christ" (Ephesians 4:11-13 NASB Updated, my emphasis).
- the role of a pastor/teacher involves teaching, but not every teacher is a pastor, nor is every pastor called only to teach, but to shepherd the flock through teaching, exhorting, preaching, rebuking, encouraging, discipling, and providing leadership to elders and deacons (though in some denominations, "the pastor" is also accountable to the elders), to name just a few of the tasks associated with the role of a pastor/teacher. We must keep in mind, however, that the lead pastor in a church does not possess all the gifts, and wise is the leadership in a church who encourage a lead pastor to function within his area of giftedness and not burn out by either using that giftedness or by attempting to function in an area in which he is not gifted!
In conclusion, I myself am an example of a teacher who is not a pastor. My calling of God is as a teacher. My role, almost from its nascency, has been as a scholar/teacher. My bent from the very beginning has been to
"Be diligent to present . . . [myself] approved to God as a workman who does not need to be ashamed, accurately handling the word of truth" (2 Timothy 2:15 NASB Updated).
Frankly, I have never "aspired to the office of overseer [i.e., bishop/episcopos], content by being just a teacher to the body. This is not to say I will never aspire to the office of bishop, but at 64, it's beginning to look less and less likely!