How was Paul able to give believers the deep doctrines in his letters?
Paul was able to give believers the deep doctrines in his letters because he was privileged by the work of the Holy Spirit to do so. His letters are written only to believers, not the unsaved world, and they explain truths such as dying and being raised with Christ for spiritual growth.
Les explains that Paul's letters are addressed exclusively to believers, not to the unsaved world, though that does not mean they are inappropriate for them. The deep doctrines—such as dying with Christ and being raised with Him—are not required for salvation; even new, untaught people do not need all these deep doctrinal things to be saved. But once someone becomes a child of God, God expects learning, growth, and a graphic understanding of all that God has done on our behalf. Les sees the problem with much of mainstream Christianity as stopping at the elementaries and never going into the deeper things, leaving no understanding of these deep doctrines that Paul was privileged by the work of the Holy Spirit to give in his letters.