Who is Paul writing to when he describes those under the control of old Adam?
Paul writes to believers, the saved, not to the unsaved world. Even when he describes those under the control of old Adam, his letters are addressed to us believers so that we may learn, grow, and understand all God has done on our behalf.
Les teaches that all of Paul's letters are written to believers, not to the unsaved world. They may be appropriate for the unsaved, but Paul is not writing them to them; he writes to the believer. Therefore, even the things said about those under the control of old Adam still come from Paul's pen, but he is writing them to us. Les explains that believers do not have to know all these deep doctrinal things to be saved, but once we become a child of God, God expects us to learn, grow, and get a graphic understanding of all God has done on our behalf. This deeper understanding is what much of mainstream Christianity lacks.