“The two chief characteristics of the false teachers are that they were troubling the church and changing the gospel. These two go together.
To tamper with the gospel is always to trouble the church. You cannot touch the gospel and leave the church untouched, because the church is created and lives by the gospel.
Indeed, the church’s greatest troublemakers (now as then) are not those outside who oppose, ridicule and persecute it, but those inside who try to change the gospel. It is they who trouble the church.
Conversely, the only way to be a good churchman is to be a good gospel-man. The best way to serve the church is to believe and to preach the gospel.
The devil disturbs the church as much by error as by evil. When he cannot entice Christian people into sin, he deceives them with false doctrine.”