1 John (1974)
There were many false teachers who had given false hope to some and dashed the assurance of some Christians. John addresses the question what are the distinguishing marks of a true believer, are these marks in your life.
2 & 3 John (Two Series) (1978) (1997)
These two short letters from the Apostle John are written to ordinary believers, to explain how to recognise true and false Christians by their love and by their life. Do they love the truth of God or themselves, do they obey God or follow their own ways.They deal with important attributes of the Christian, namely fellowship and character respectively.