When we read through the New Testament, we see that the bar is really high for pastors and teachers in the church, because they have a huge responsibility. And the church is right to set safeguards to keep bad leaders away. When leaders mess up and teach something false, they are likely to take other people down with them. So anyone in leadership—pastors, teachers, mentors, elders—should be humbled by this warning. They must make sure that their teaching and actions line up with God’s will.
Jesus warns that you can’t trust a false teacher or leader, and he points out that you can recognize them by their fruit (actions). If a leader is unfaithful to their spouse, if they are selfish with money, if they play favorites in the community on the basis of wealth or status or acting like bigshots, if they never apologize or acknowledge their own sin, they are dangerous to the community. And they must be dealt with accordingly.