The apostle John says we know love in that Jesus laid down his life for us; so we ought to do it for our brothers (1 Jn. 3:16). John would know. This is exactly what his brother James did for him, the church and Jesus as he was murdered at the hands of Herod (Acts 12:1-2). I find it easy to forget that the writers of the New Testament knew such suffering themselves. John must have had his brother in mind as he wrote that.