Does a believer have two natures?
Yes, absolutely. A believer has two natures: the old Adamic sin nature that constantly pursues him, and the new divine nature received through salvation and union with Christ. This is Pauline doctrine: the old sin nature wars against the new divine nature, and the old Adam must be kept in subjection and reckoned dead.
Les explains that the question "Do I believe in two natures for the believer?" was answered in a newsletter, and his answer is "Absolutely." He teaches that the believer still has the old nature—the old Adam that constantly pursues us—and also has the new nature as a result of the salvation experience and union with Christ. This is a Pauline doctrine, a constant warfare between the old sin nature and the new divine nature. In speaking of Dying Daily, Les says the old Adam must be kept in subjection and put to death. He points to Romans 6:13 and throughout Romans 6, where Paul deals with reckoning old Adam as our mortal enemy and putting him constantly to death. God, in His omnipotence and sovereignty, reckoned our old Adam as crucified with Christ the moment we believe, so he is dead; but in experience he is still with us and plagues us until we leave this body of mortality.