If you instruct the brothers of these things, you will be a good servant of Christ Jesus, nourished in the words of the faith, and of the good doctrine which you have followed.
Jesus died for the sins of the world. But only those who believe receive the forgiveness of sins. Jesus died to redeem the world, but He will only take His treasure out of it. And so He died and is the Saviour of all men, but specifically those who believe. He provided salvation for all men, but not all have received it.