The purpose of this book is to give assurance (5 v13). John has focused on the first test of obedience (2 v1-6). John now focuses on the test of love.

God is pure light, and part of the purity is perfect love (v7-8). John undoubtedly had in mind Jesus’ words in the Upper Room (John 13 v34-35).

James Montgomery Boice says this commandment is new in the extent to which it reached, the lengths to which it would go and the degree to which it is realised. Jesus gives anew understanding of what it means to love.

This light enters the believers and brings a new love within them from their experience of Christ (v8). Part of God’s light is love and therefore those who walk in that light must walk in love (v10). Hatred of others and particularly of other Christians, is a part of the darkness and not light (v9 & 11).

Walking in the light means the person will not stumble (v10b), whereas walking in darkness means blindly stumbling along (v11).

Normally a part of hatred is pride, feeling superior to others, but John teaches here that hatred actually shows blind ignorance. Hatred is a strong word, but John uses it because he recognises it’s a real danger in the church.