1 John 4:1
 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world. (ESV)
Have you ever heard someone declare, "We are not supposed to judge."? Many Christians refuse to stand against anything that a teacher says because they do not want to be guilty of judging another "believer." They take this from Jesus' words in Matthew 7:1 where he said, "Judge not, that you be not judged." So, while we must obey Jesus' words we must also know what he meant.
When Jesus instructs us to not judge others he is referring to a self-righteous kind of condemning of another brother. In other words, we are not to look to ourselves as the authority over another person. God is the one who judges, and the standard of judgment that he uses has been revealed in his written word, the Bible.
Now, as we look at what the Apostle John tells us here in our verse today we come to a kind of judgment that we are instructed to have. John tells us to test the spirits. That action of testing requires a kind of judgment, or discernment. I am convinced that most Christians not only fail at this instruction to test the spirits, they are so Biblically illiterate they are incapable of such a test.
"Most Christians not only fail at this instruction to test the spirits, they are so Biblically illiterate they are incapable of such a test."
The church from the beginning was infiltrated with false teaching. John writes this Epistle to deal with the false teachers who had already done much damage in the church. He tells us here that behind every false teacher is a false spirit. The same is a reality today. There are many false teachers. And behind their voice is a false spirit attempting to deceive and destroy the body.
If you are going to be a disciple of Jesus Christ, learning to test the spirits needs to be a part of your life. Gullibility is not a godly trait. Are you up to the task of testing the spirits?