1:3 Charge certain persons not to teach any different doctrine
Teaching shapes the church. The church will be shaped, either truly or falsely, so the charge given to Timothy, and to pastors ever since, is to teach the truth, truthfully. Actually, it’s stronger than that: the instruction is that those teaching what is false are to be stopped. In this instruction Paul seems less concerned that ‘every voice must be heard’ than that the church doesn’t waste time getting distracted by what is false. That must have been a tough sell in first century Ephesus, just as it is in the 21st century West.

2:5-7 There is one God, and there is one mediator between God and men, the man Christ Jesus, who gave himself as a ransom for all, which is the testimony given at the proper time. For this I was appointed a preacher [‘herald’] and an apostle…a teacher of the Gentiles in faith and truth.
As a summary of the gospel this ‘testimony’ is as good as it gets: This is who God is; this is who Jesus is; this is what Jesus has done. Brilliant! What we also see is the extent to which Paul’s ministry was defined by teaching. Teaching was what he did. The gospel was heralded, and then it was consistently taught. Paul was unique, but the pattern of teaching he modelled was embedded in the practices of the church: there is meant to be teaching in the church. And this helps explain what in a WEIRD culture (see here) is probably the most contentious verse in scripture…

2:12 I do not permit a woman to teach or to exercise authority over a man
What exactly ‘authority’ means here has been hotly debated (including here) but what is clear is that there is an authority about teaching – or, there is teaching that is meant to be done with authority. And seeing that helps explain the weight Paul puts upon an elder’s ability to teach…

3:2 An overseer must be…able to teach.
There are different contexts for teaching, and yes, I think the ‘Big-T/Little-t’ distinction is helpful, and scriptural. There is teaching that overseers are meant to do, and there is teaching that everyone in the church is called to do (Col. 3:16 Let the word of Christ dwell in you richly, teaching and admonishing one another in all wisdom). But teaching is tied to eldership because it is one of the means by which the health of the church is preserved, and elders are responsible for this health. It is interesting to note that the very similar character requirements for elders and deacons do not have a corresponding teaching requirement. Elders are guardians of the flock and part of the way by which they guard it is by teaching – something that is not expected of deacons. As elders teach, they equip the flock to discern right from wrong, which helps explain this verse…

4:5 Everything created by God is good, and nothing is to be rejected if it is received with thanksgiving, for it is made holy by the word of God and prayer.
Teaching the word is central to the life of the church because it is by the word we are equipped to receive all the good things God has for us. Paul can’t keep himself from underlining this…

4:11 Command and teach these things.
Teach the truth. Teach the truth. Teach the truth! And, do this…

4:13 Devote yourself to the public reading of Scripture, to exhortation, to teaching.
Note here that the focus is on public scripture reading, exhortation and teaching. That is, Paul has in mind a different setting than one on one teaching, or the kind of Colossians 3:16 teaching that might go on when a small group of believers meet together in a home. Not all gatherings of the church are alike, and for most of us, Sunday morning is the ‘public’ space. This is a space that is in large measure defined by teaching, and Paul clearly expects that to be the task of the elders. Which is why he goes on to say…

5:17 Let the elders who rule well be considered worthy of double honour, especially those who labour in preaching and teaching.
Preaching and teaching is labour. I know this from personal experience: public teaching is both the most rewarding and exasperating thing that I do! Not all leaders (or even all elders) are meant to carry out this public ministry, but those who do are to labour at it because it is how the church is shaped. What is taught in the church really matters…

6:2-4 Teach and urge these things. If anyone teaches a different doctrine and does not agree with the sound words of our Lord Jesus Christ and the teaching that accords with godliness, he is puffed up with conceit and understands nothing.
With this instruction Paul brings us back to where we started in 1:3: if the church is going to head in the right direction then right teaching is non-negotiable.

Teaching is certainly not the only leadership role in the church, and we should fight very shy of building preaching centres: we don’t want preaching centres – we want churches! But without truthful teaching there isn’t a church to lead; or something is being led, which isn’t a church. As it was in Ephesus, so it is today.