In doing this, he appealed to them to judge their teachers' teaching. This letter seems to assume that the gospel is clear to Christians and churches. We are to judge everything by the Word of God. If it is different from what we have in the Bible, we have the responsibility to reject it. We need to be willing to enter controversy when the message of the gospel of Christ is at stake.
Christian denominations have an amazing agreement about the gospel.
Our loyalty and faithfulness are ultimately to the gospel, and it is this that all true Christians hold. That good news has not fallen into a million pieces. Theological controversy may be unpleasant, but it may be necessary. It is our responsibility to believe the real gospel for ourselves and to make sure it is taught to others, even if it involves us in controversy. We may not please men by living this way, but we will bring pleasure to God.