Salutations

“Grace and Peace”—Common introduction in Greek epistles to Jewish people. It uses both the common Greek greeting and the common Hebrew greeting.

This probably implies, like Paul's churches, that the churches John was writing to were mixed between Jews and Gentiles, between Hebrew culture and Hellenistic culture. This is no surprise, since Paul ministered in this same area-- Asia Minor-- and two of the churches were in Paul's realm of concern-- Ephesus and Laodikia.