John 4:1 Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.
Now as John starts chapter 4 we see he is asking us to to test the spirits and the the teachings of everyone. We know today that there are many false teachers of the word of God in the world today as there were in John’s day. The difference in the false teachings of today and back then is that today most false teachers do it by just changing enough of the gospel to make it mean what they want it to mean. A lot churches today like to water down the word of God so it does not step on peoples toes. The only way to know if it is a false teacher or prophet is to know what the the word of God says by reading it and studying it for yourself. To many people today want to go to feel good church on Sunday morning and think that is all they need to get to heaven. Guess what they are probably being taught by a false teacher. The Bible tells us that the Antichrist will come and any who is teaching a false doctrine is an Antichrist. I could go on about what this verse implies but I will end in saying know the word of for yourself to know if you are listing to a true man of God.