Later on that same evening of the Last Supper, Jesus gave one more statement on the evidence for true discipleship. He was comparing himself to a vine, with the disciples as the branches. His focus was the goal of fruit-bearing. Branches that bear fruit are pruned so that they will bear even more. Only those branches that remain in the vine are capable of bearing fruit. And God is glorified when much fruit is borne. But more than that, abundant fruitfulness is the mark of true discipleship. This is the fourth mark of a disciple [Read John 15:5,8]. A little further on, in verse 16, Jesus says, “I chose you and appointed you to go and bear fruit—fruit that will last.” What is fruit? It is what the vine produces when it is healthy and mature. Fruit includes the character qualities of Jesus listed in Galatians 5, where the apostle Paul says...