You're right, but Mac's books were designed to refute a false doctrine that had crept into our churches - that you could claim Christ as your savior and then possibly, at some later date, if you want to, start living as a Christian and trying to follow Christ. He was concerned because according to all the previous generations of Christians that we have access to, Puritans, Methodists, Arminians, Anabaptists this type of thing was unheard of until a few years ago. His books were designed to be helpful to laymen like us but they probably should not be used as a theology manual.