By the time the Apostle John wrote this letter he was an old man. He had been imprisoned on a convict island: most, if not all, of his fellow apostles had died violently. Persecution threatened the church. And yet the church grew. Then false teachers undermined the gospel with heresy. Yet John was not shaken! He knew that Jesus really was God who had come as a human to atone for the sins of the world. So he writes this letter to scattered groups of Christians to help them stay close to Jesus, reject false teaching and tell others about Him.

Most human beings like to think that they are right, and in the right with everybody else, especially God. That is how God designed us to be and such relationships are a template of heaven. However we are not like that all the time. So how do we cope with the tension between our creation design to be righteous and the reality of our unrighteousness?

Love is not primarily an emotion. We may feel lovingly towards someone or experience the emotional warmth of another's love, but love is much deeper and more active than the way we feel. True love is always expressed in action; like God's love was shown by giving His Son to be our substitutionary sacrifice. The believers who John was addressing were being caught up by Gnostic teaching which claimed that if you have a special religious formula and mental attitude you can know God: but John said you do not need a formula – you need love and obedience.

Many different sorts of people meet together in churches. How do you know those who are truly walking with Jesus? John sets the test of brotherly love: those who claim to be 'in Christ' are 'in the light' and should love their brothers and sisters who are also 'in Christ'. Through the blood sacrifice of Jesus Christ they have been made children of God – and have a blood relationship which should be cherished.