False spirits must be distinguished from the Spirit of God. The most obvious way you know if someone is a false prophet is if they deny that Jesus came in the flesh and was from God! (See the REFLECTION section for more details about heresy in John's day). Reliance on God is the key to resisting the "one who is in the world" (Satan). Thoughts and teaching that come from the enemy always have an appeal to people who are not relying on God and are into the world (Romans 12:1-3, 1 John 3:15,16).
John now turns back to his previous subject: love. God is love. If we are intimate with God, we will overflow in love for others. God's love was proven when He sent His only Son whom we are to live through, and the Holy Spirit will bear witness of this in our experience of the Spirit. This is a repeat of what John said in 3:24. Here is a concise way to say it:
When a believer loves, he is drawing that love from God’s Spirit (cf. Rom. 5:5), who is also the Source of his confession of Christ (1 John 4:2). Thus both the faith and the love enjoined in the dual “command” of 3:23 are products of the Spirit’s operation in a believer. A believer’s Spirit-led obedience becomes the evidence that he is enjoying the mutual abiding relationship with God that John wrote about.
(The Bible Knowledge Commentary: Volume 2, p. 899)If we love, we need not fear (and can even be bold) in the coming judgment because "perfect love casts out fear" (4:18). If you do not love your brother or sister, John says you are a liar and not a lover of God.
Most of the eyewitnesses to Jesus' ministry had died by the time John composed this letter. Some of the second- or third-generation Christians began to have doubts about what they had been taught about Jesus. Some Christians with a Greek background had a hard time believing that Jesus was human as well as divine, because in Platonic thought the spirit was all-important. The body was only a prison from which one desired to escape. Heresies developed from a uniting of this kind of Platonic thought and Christianity.
A particularly widespread false teaching, later called Docetism (from a Greek word meaning "to seem"), held that Jesus was actually a spirit who only appeared to have a body. In reality, he cast no shadow and left no footprints; he was God, but not man. Another heretical teaching, related to Gnosticism (from a Greek word meaning "knowledge"), held that all physical matter was evil, the spirit was good, and only the intellectually enlightened could enjoy the benefits of religion. Both groups found it hard to believe in a Savior who was fully human.
John answers these false teachers as an eyewitness to Jesus' life on earth. He saw Jesus, talked with him, touched him -- he knew that Jesus was more than a mere spirit. In the very first sentence of his letter, John establishes that Jesus had been alive before the world began and also that he lived as a man among men and women. In other words, he was both divine and human.
Through the centuries, many heretics have denied that Jesus was both God and man. In John's day people had trouble believing he was human; today more people have problems seeing him as God. But Jesus' divine-human nature is the pivotal issue of Christianity. before you accept what religious teachers say about any topic, listen carefully to what they believe about Jesus. To deny either his divinity or his humanity is to consider him less than Christ, the Savior.
(Life Application Study Bible NIV, p. 2281)
What do you believe? Think through it. How would you explain this to someone who did not believe?
Further challenge: Go out and talk with someone who does not believe (you can even tell them it is an application from your Bible reading)! Do not argue but listen and try to understand. You will probably build a bridge and make a friend in the process.
Help us to grow in our understanding of who Jesus is. Help us to build bridges with others who may not believe the same. In Jesus' name we pray, Amen.