What does the Bible say about itinerant preaching?

In 2 John 1-10, the Apostle John instructs believers to closely examine any itinerant preacher's doctrine. He warns that those who do not confess Christ has come in the flesh are deceivers and do not have God. This underscores the need for the church to evaluate any teaching against the established truth of Scripture. The passage highlights that only those who remain in the doctrine of Christ can genuinely claim to have fellowship with the Father and the Son. Thus, sound doctrine is foundational to true fellowship and spiritual growth.