What is the first book of doctrine that Paul wrote?

The first book of doctrine that Paul wrote, at least in the New Testament, is Romans. In the supplied teaching, Romans is identified as the first Book of Doctrine Paul writes, and it is where most time must be spent.

Les teaches that Romans is the first Book of Doctrine that Paul writes, at least in our New Testament, and this is where we have to spend most of our time. The context connects this to Paul's writings alone, since the truth about believers becoming members of the Body of Christ is not taught in the Gospels or the Old Testament. Paul is constantly at it, teaching that when we have faith in the Gospel, we become members of the Body of Christ.

Which book is Paul's first book of doctrine in the New Testament?

Romans is Paul's first book of doctrine in the New Testament, at least in our New Testament. The context identifies it as the first Book of Doctrine Paul writes, and it is the place where most of our time must be spent.