Now we can understand why John worded portions of his epistle two different ways. (1) He told about evil ones, grievous wolves, who had never been of the Church. They had a wolfish nature when they entered, and they were still wolves. In other words, while they professed Christianity, there was no change in their conduct. (2) John also told of a class that arose within the Church speaking perverse doctrines. They were of the truly consecrated, but they began to err and go out of the truth. Thus there were two different classes.
In this first epistle, then, John went back and forth in speaking of the two classes. He said that those of the grievous wolf class were of the devil—they were of the devil previously, they were of him now, and they would be of him in the future. Those of the other class left of their own volition. They tried to draw disciples by dividing the class and getting some to leave.