The letters of 2 and 3 John are the shortest books of the New Testament, shorter even than Jude or Philemon which also each have only one chapter. But this does not mean that either 2 or 3 John is insignificant. To be sure, in some ways each merely repeats the general message of 1 John, which is longer. But the repetitions are made in two distinct contexts which in turn give a unique direction to the letters and call forth new emphases.
The immediate problem in each book is that of traveling teachers or missionaries. According to Christian ethics all who thus traveled about were to be shown hospitality by Christians in the town to which they came. In this, Christians were doing what the best of non-Christians would also do. But in Christian circles this extension of hospitality was open to obvious abuse and raised moral questions as well. For example, suppose the visiting teacher claimed to be a Christian missionary or even a prophet but taught what was clearly false doctrine. Hospitality would demand that he be provided for, but to do so would seem to be participation in the spread of his false teachings. Should he be received or not? Or again, suppose the teacher overstayed his welcome or asked for money, thereby giving evidence of being motivated more by greed than by a desire for Christian service. How long should such a one be tolerated? Should money be given? The extent of this problem in the early church age is seen in the fact that the Didache, another early document, deals with the problem at length and even invents the term “Christmonger” to describe those who attempted thus to profit by Christianity.
The letters of 2 and 3 John deal with these problems and also share other Christian teaching incidentally. In 2 John the author seems to be writing to a local church. So here the issues are discussed in the broadest terms. First, the author reminds his readers of the tests of true Christianity which have already been developed in the earlier and longer letter. Second, he warns them to be on guard against false teachers. In this case the test of truth and error is the test of Christian doctrine, particularly as it relates to Jesus as the Christ come in the flesh.
In 3 John the negative approach (“receive him not,” that is, the false teacher) gives way to a positive encouragement to receive those who really are the Lord’s servants. Several distinct personalities are in view. The letter is written to a Christian named Gaius. He is commended for having shown hospitality to teachers who had visited his area and is encouraged to continue showing it. Diotrephes is the second person mentioned. He is rebuked indirectly for his refusal to welcome the same teachers and for trying to keep other Christians, such as Gaius, from doing so. Finally, mention is made of a third personality, Demetrius, whose example is said to be a good one. These two letters, the one warning against receiving and encouraging false teachers and the other encouraging a genuine hospitality toward true teachers, belong together.
