It sounds pretty easy doesn’t it? Love one another. John’s letter (1 John 3:11-20), merely reinforces what Jesus himself had said in John 13:34. One minister I heard of stood up on Sunday morning and preached just this text for his sermon. Then he sat down. The next week, he preached the same message, ‘love one another’ and sat down. By the third Sunday, his congregation were getting uneasy. Then he did it again. Finally they understood. They had to actually practice what they had heard. Love is shown by our actions (1 John 3:16-17). The church became transformed and grew.
John makes a contrast between the person who loves their fellow Christian and those who claim to be a member of the church, but hate their fellow believer (1 John 3:12-15). They are like Cain who hated his brother Abel and murdered him. To hate is as good as murder. It also shows that the person who hates, remains in a place of death, not living in the life of God through his Spirit.
Why does John state things so bluntly and starkly? Because how we speak to each other, how we treat each other and how we fail to care for each other, indicate our love or lack of love. Those who speak ill and mistreat their fellow believer, do not demonstrate that they have passed from ‘death to life’ (1 John 3:14).
Love is the hallmark of a true believer. Jesus said: ‘By your love people will know you are my disciples.’ (John 13:34) No love, no indication that you are a disciple of Christ, and this in turn, is no indication that you really belong to God, or live in Christ. (1 John 3:23-24)