3 John is a personal letter written to an individual named Gaius (a fairly common name.) The letter was written to address a specific matter of providing hospitality for Demetrius – this hospitality was being denied by another local leader named Diotrephes. Key Learning: Do not forget to show hospitality to strangers.
Even in the first century human begins behaved like human beings. Power struggles, striving for position and the occasional snub lead to an intervention by the Apostle John. John is the founding pastor and has the apostolic authority for this region -- for Diotrephes to resist this authority was to reject his spiritual head. John's solution is to contact another prominent person in the church, Gaius, and have him intervene on his behalf. The resolution of the dispute is never recorded.