At the time John wrote, the church was confronted with error. Many false prophets were spreading error across the world. As the text implies, these false prophets were claiming that they were inspired by the Spirit of God. Yet, they were teaching error.
John had just told the believers that they know Christ abides in them and they abide in Him because of the Spirit whom Christ has given them. Now, in our text, John exhorts the believers to "test the spirits to see whether they are from God." He not only exhorts them to test the spirits, but he also gives them the tests to apply.
Some of the spirits mentioned in this text are from God while others are not. Both types of spirits speak. It is the false prophets and the believers who speak. We could think of them as spirits, but spirits do actually exist as well as people. So it is better, in my view, to hold that the people are inspired as they speak.
One, there are many false prophets: Beware!
Even in John's day, there were many false prophets. Collectively, the spirits inspiring the false prophets may be described as the "spirit of antichrist" or the "spirit of error." These evil spirits are under the control of the devil. They are against Christ and do not recognize or confess Him.
Today, as in the ancient church, many forces are arrayed against Christ. One of the most serious errors of the day is that there are many roads to salvation. The uniqueness of Christ as the Son of God is denied. Much of the error has to do with wrong views about Christ.
Two, Do the spirits confess that Christ has come in the flesh?
The first test has to do with the confession of the believers. The believers are inspired by the Spirit of truth, the Holy Spirit. There are good as well as evil spirits. The good spirits are aligned with the Spirit of truth. These spirits confess that Jesus Christ came in the flesh, and they are from God. They hold to the truth that Jesus is both divine and human.
The false prophets either minimized or opposed the idea that Christ came in the flesh. To counter this, John presents basic gospel truths. According to Burge (p. 174-175):
Behind these words [verse 3] John is urging three things about our belief: (1) that the man Jesus of Nazareth is indeed the divine Word of God; (2) that Jesus Christ was and if fully divine as well as human; and (3) that Jesus is the sole source of eternal life since he alone reveals the Father to us and atones for our sins.
Three, Who is listening to the spirits?
John presents another test. This test has to do with who is listening to the messages being proclaimed. In verse 5 John shows that the false prophets and the world are in perfect agreement. Those who celebrate the teachings of the false prophets are of the world. In contrast to them, the true teachers are from God. He who knows God listens to the true teachers and prophets.
The Holy Spirit inspires those who are from God. Burge states (p. 176): "There is also a harmony, a correspondence, between the Holy Spirit in the believer and the Holy Spirit in the prophet. When God's Spirit inspires a prophet, his people will discern God's truth." The people of God know His voice and respond fully to Him.
Four, the believers overcome the false teachers.
John begins verses 4-6 by saying that the believers have overcome the false teachers. God abides in them, and He is greater than "he who is in the world." As Robertson (p. 230) points out, "God is greater than Satan, 'he that is in the world' (ho entoi kosmoi), the prince of this world (John 12:31; 14:30), the god of this age (II Cor. 4:14), powerful as he seems."
John was confronted with false prophets who were teaching error concerning the Incarnation of Christ. Because of this, he exhorted the church to tests the spirits. They could test the spirits by evaluating what teachers were saying about the Incarnate Christ and by observing who was listening to them.
Today, the church encounters many errors. As in the days of John, we must always rely on the basic truths of the gospel. Now, we have the New Testament in its full form. The Word of God is our surest guide to the truth. The teachers who conform to God's Word are from God. Moreover, God's people listen to them.