As I am working through 1 John, a variety of pertinent issues continue to come up, and certainly several come up from careful scrutiny in 1 Jn. 4.1-6. Our author is talking about testing the spirits, which is another way of talking about testing the source of one's own or another person's inspiration. One of the interesting features of the discussion in this text is that the author does not deny that the false teachers/prophets are inspired or guided by some spiritual source, he simply says that what they are saying isn't true and therefore they are inspired by nefarious spiritual influences. In short, inspiration is no guarantee of truth, any more than a profound religious experience is a guarantee that it comes from a good source. Apparently, it is a good rule in spiritual matters to 'consider the source'.
Our author views the spiritual world as follows: 1) there is both a Holy Spirit and a Satan both of them capable of inspiring certain thoughts and actions. It is possible our author is also thinking of demons indwelling and inspiring people, but demons are nowhere mentioned in this sermon. What is referred to is the Holy Spirit indwelling believers; 2) the human spirit picks up the signal, so to speak from its spiritual source--- whether God or the Devil; then 3) the spiritual person speaks some inspired and apparently also inspiring words.
As it turns out inspiration is not a guarantee of the content of the inspired statements being true. Thus criteria have to be applied to discern who is a true prophet and who a false one. Our author applies two interesting criteria, and here he is drawing on Deut. 13: 1) the person who makes a true confession about Jesus being the Christ or the Son of God or the Savior come in the flesh is obviously inspired by the Holy Spirit because as 1 Cor. 12.3 says, no one can make such a true confession except by the Holy Spirit; 2) the person who loves the brothers and sisters and lives a righteous and holy life is obviously someone who has the Spirit of God dwelling in him or her. In other words, there is both a test of orthodoxy and a test of orthopraxy to determine whether one is inspired by a true and godly source or not.
Of what relevance is this to us? I am tempted to say with another Biblical writer 'much in every way'. Our culture has a major problem discerning the difference between earnestness and truth, or even honesty and truth, and also between enthusiasm and truth, or 'being inspired or spiritual' and truth.
Our author warns us that inspiration, enthusiasm, earnestness, even honesty about what one believes is no guarantee of truth. You can honestly confess you believe something and be dead wrong. This is precisely why our author relies on more objective criteria-- what does this prophetic voice actually say or teach, and how does this person live. The latter is something on the order of "you shall know the tree by the fruit it bears" but also a 'true Christological confession' is crucial. There is a lot of teaching that goes on in the church today that could not pass the Beloved Disciple's Christological test, much less his sanctification test. In our author's view true love, love of God and of others, has a particular Christological shape-- it looks like the life and teachings of Jesus, and one might add the life and teachings of his eyewitnesses and apostles. It does not look much like the 'true confessions' or lifestyle of many preachers and scholars who have gained wide fame and appeal in America in the last century. We should be asking, what is wrong with this picture?
It is not of course easy to sort out the difference between spiritual truth and error, Christological truth and error, ethical truth and error, and this is one of the reasons our author urges that such issues be sifted, critically sifted using reasonably objective criteria.
1 John 4.1-6 is a clarion call to critical thinking about spiritual matters. Open-mindedness can be a good thing, but if you have no criteria by which to sift what you hear and learn, you are in trouble. As my grandmother used to say--- "Don't be so open-minded that your brains fall out." This is especially true when it comes to discerning the truth about Jesus, about the Christian life and how it ought to be lived.