Many different 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 (1 John 1:7).

But John was writing to churches where false teaching had seduced some to become proud of their spiritual enlightenment.  They despised others in the church.  Love was lost.  Indeed, relationships became so polarised that they hated each other.  John said that claiming to be in the light with Jesus is incompatible with hating another believer (1 John 3:16-18).  At least one of them is really walking in darkness, blinded to the true gospel and the liberating grace of Christ.  In that state, they do not know where they are spiritually, nor do they know which way to go and cannot help others (Luke 6:39).

On the other hand, when brothers and sisters are enjoying the Lord's presence, they want to behave in a way which pleases Him so that they can live like Him.  When that is the shared focus for a group of believers, nobody is tripped up; they grow together in love because they all grow towards the Light who is also Love.  When that happens, the demonstration of love by very different people for each other has an evangelistic impact (John 17:20-21).

It is not easy to get on with everyone, but love must be the rule (Romans 12:18).  Some, who are trapped by their own selfish desires, cannot enjoy close fellowship with the rest of the church - but the church should still love them and long for them to come to repentance.  Others are snared by wrong teachers who may appear to be sincere, but they will lead others into darkness – so it is important to teach the truth to let in the light.  When the light of truth is welcomed, the love of Christ replaces hatred.  Wherever you see the darkness creeping in to induce hatred, challenge it with God's Word and practical love.  In the home, at work or in the church, make love your aim (1 Corinthians 14:1).