Rev. 2:20 "But I have this complaint against you. You are permitting that woman--that Jezebel who calls herself a prophet--to lead my servants astray."
What kind of preaching do you listen to? In some of the early churches, false teaching entered in. There were people who were proclaiming a different message than the Gospel message and it was leading people of the church astray. We don't know all that was being taught, but we do know that it could not have been consistent with Paul and the apostles' teachings. Many wanted to cling to their traditions and old ways of living in their walks of faith. Many used the Gospel for their own personal gain.
There are a lot of different things being proclaimed in the church today that are different than what is proclaimed in God's Word. Some churches have changed the Word of God to suit their own interpretations of it. Some have softened the message and no longer preach about God's holiness. Some declare that hell is not real and we don't have to concern ourselves about it. Some take a more universalistic approach and declare that there are many ways to God other than Jesus. There are so many different spins on the truth of the Gospel that the Word of God is no longer considered to be infallable and relevant to our daily living. Some add to it and take away from it what they want in order to suit their own whims.
It is imperative for the wellness of our souls that we be diligent students of God's Word. We must not take an intellectual approach to the Word without a heart approach. We must let God speak to us and guide us into all truth. We must submit to its authority over us and have nothing to do with any teachings that go contrary to it. God has clearly made known to us the way of holiness and we must follow it. Without it, no one will see God.