Why are Matthew, Mark, and Luke called the Synoptic Gospels but John is not?
Matthew, Mark, and Luke are called the Synoptic Gospels because all three deal with Christ in His humanity: Matthew as King, Mark as servant, and Luke as Son of Man. John is not grouped with them because it depicts Him as the Son of God in His deity, highlighting His divine nature instead of the human side.
Les explains that Matthew, Mark, and Luke are grouped as the Synoptic Gospels because all three deal with Christ in His humanity. Matthew depicts Him as the King who would one day rule on David's throne, coming through Abraham, Isaac, Jacob, and David's royal family. Mark depicts Him as the servant, showing His willingness to serve from His human side. Luke depicts Him as the Son of Man, constantly presenting that human side. John, however, depicts Him as the Son of God in His deity. As an illustration, Matthew, Mark, and Luke all give the account of His wilderness temptations, but John does not, because those temptations affected His human side but had no effect upon His deity.