A trustworthy saying

"The saying is trustworthy and deserving full acceptance: Christ Jesus came into the world to save sinners, of whom I am the foremost" (1 Tim 1:15)

Paul often had to fend off bad teaching. And he does so by going back time and again the gospel - which is the heart of all good teaching. In 1 Timothy 1, Paul points out a few effects of this kind of gospel teaching:


It moves people into ministry
Paul says that bad teaching leads to "speculations" while good teaching promotes "stewardship from God, that is by faith" (1 Tim 1:4). Gospel teaching pushes people to use their time, talent, and treasure for the kingdom.


Love
"The aim of our charge is love" (1 Tim 1:5). Jesus says love is the fulfillment of the law (Mark 12:30-31). When we sit under good teaching, we will have more love for God and for other people, precisely because we are overcome with the love of God for us made tangible in the gospel.


Worship
"To the king of ages, immortal, invisible, the only God, be honor and glory forever and ever" (1 Tim 1:17). Paul regularly breaks into praise as he writes, especially when he's doing serious theology. Good theology makes for great doxology. Ruminating on the gospel will lead to worship.


Christian Maturity
Good teaching helps people stick with it for the long haul. Paul writes to Timothy to help equip him for "warfare" (v.18) - for their will be many assaults on your faith (persecution, doubts, suffering, temptation). Good teaching grounds you in the gospel and gives you the resources to press on through difficult periods.