In his letters, John expresses delight at believers who are "walking in the truth" behaving with that integrity which reflects the gospel. This involves not just correct doctrine and proper outward behavior, but also love for God and fellow believers. It's this love, John writes, that shows that the truth of the gospel has really been grasped, not as an abstract idea but as what it is, the very life of God himself at work in his people. These nine...