The Book of 2 John is addressed to “the chosen lady and her children.” This could either have been a lady of important standing in the church or a code which refers to the local church and its congregation. In those days when Christians were being persecuted such coded salutations were often used.
The Book of 2 John is largely concerned with an urgent warning concerning deceivers who were not teaching the exact doctrine of Christ and who maintained that Jesus did not actually rise in the flesh but only spiritually. John is very anxious that true believers should be aware of these false teachers and have nothing to do with them.
For a more detailed summary select the link below.
The Book of 2 John Summary