1 John: This letter emphasizes the importance of love in the Christian life. John emphasizes that God is love and that those who abide in God must also abide in love. He warns against false teachers who deny that Jesus is the Christ, and encourages believers to hold fast to the truth of the gospel.
2 John: This short letter emphasizes the importance of truth in the Christian life. John urges his readers to love one another and to walk in obedience to God’s commandments. He warns against false teachers who deny the incarnation of Jesus, and encourages believers not to receive such teachers into their homes or to support them in any way.
3 John: This letter is addressed to a man named Gaius, who is commended for his hospitality to traveling missionaries. John also warns against a man named Diotrephes, who is causing division in the church by refusing to receive the missionaries. John encourages Gaius to continue to do good and to imitate those who do good, while warning against those who do evil.