Who is Paul's teaching about being under the control of old Adam written to?

Les explains that all of Paul’s letters are written to believers, not to the unsaved world. The teaching about those under the control of old Adam still comes from the pen of the Apostle Paul, but he is writing it to us. Paul goes into deep ramifications of how we died with Christ and were raised with Him, even though we are already saved. These deep doctrinal things are not required for salvation; new, untaught people do not have to know them to be saved. But once we become a child of God, God expects us to learn, grow, and get a graphic understanding of all He has done on our behalf. Les says much of mainstream Christianity has only the elementaries and never goes into the deeper things, so it lacks understanding of the deep doctrines Paul was privileged by the Holy Spirit to give in his letters. Verse 9 confirms he writes to us believers, saying, 'that's not you.'