Having set the scene we now start looking at the letters Paul sent to Timothy, as a kind of followup instructions after journeying together and Timothy learning at Paul's side.
For both letters it is clear that Paul is worried about opposition with false teachings that threaten to undermine their work. Paul starts on this in v3, but we see it also in chapters 4 and 6, as well as 3 of the 4 chapters in the second letter. This is the big issue!
It is a headache for us because we don't know exactly what these false teachings were. Scholars try and reverse engineer, but there is alot of guess work. Why doesn't Paul spell them out? Two reasons: first Timothy worked alongside Paul, seeing first hand the issues - and so Paul doesn't need to tell Timothy about them. Secondly Paul would rather concentrate on the real deal: Jesus.
How do you tell counterfeit money from the real thing? You study the real thing in every detail. Fakes have numerous variations, but by thoroughly knowing the real thing you will know which is which. That is what Paul is doing here - he would rather concentrate on faith in Jesus, saved by grace. It is similar with his (and Jesus') attitude to evil - they don't spend ages talking about it. They acknowledge its presence (evil is real, e.g. v20), but do not give it undeserved attention.
So we are left to speculate on the issues. Broadly they were likely some who were re-applying Jewish law to Christians in an unhelpful way, others making the opposite error of claiming 'anything goes', and others who were suggesting Christians should withdraw from a society to be absolutely pure. Add to this the fact that in Ephesus there was the Greek female fertitily god Artemis which led to all kinds of ideas and practices across the region.
In v4-7 Paul makes a contrast: between Jewish law and genealogies of who is who which led to endless speculations and debates, and Jesus with his ability to save which leads to building people up, affirming them and thus ultimately love. The contrast is between boundaries or 'systems' and the simplicity of Jesus setting people free.
A big thing for us is that church is people - it is not the building, but lets remember that it is not a system either. It is people who discover grace in Jesus and want to walk with Him together.
Paul affirms the positive use of law - where it acts like a big screen projector to show up our worst failings, that this might be a wake-up call for people whose identity has been over-run by being immersed in destructive behaviours. He gives a classic 'vice list' (v9-10), but as Christians we should be careful how we use such lists, noting the breadth of the list in case we are tempted to concentrate on just one issue.
Paul then turns to grace (v12), using his own life as an example. This leads to a 'trustworthy saying' in v15, the first of around five we will find in the two letters. Paul reminds Timothy that 'Jesus came into the world to save sinners'. That is the good news in golden nugget form - we would do well to keep it that simple. When witnessing to others how complicated do we end up making it?
It this straight-talking message of Jesus coming to save that Paul wants Timothy to preach. In v1 Paul recalls his own commissioning to do that, and now in v18-20 he re-commissions Timothy for the same. These act like brackets around the whole passage. Do we point to Jesus and his ability to save, or do we actually say more about what is bad? To focus on grace is not the same as saying anything goes, but is the clear gospel message that Paul and Timothy were all about.