OBJECT LESSON: We can't know for sure, but based on the last verse of chap 14 ("Come now, let us leave"), it's likely that Jesus spoke these words as He and the disciples walked through vineyards on the way from the Upper Room to the Garden of Gethsemane. In the early springtime, the grapes have just been pruned, making a vivid contrast between the remaining branches and those thrown on the burn pile.
THEOLOGICAL AGRONOMY: If a healthy grape vine is planted in good soil, and is given plenty of sunshine and water at just the right times, it can not help but to bear grapes. It's in its DNA; in a sense, a planted grape vine must bear fruit. So it is, says Jesus, of His followers: a Christian, planted in the good soil of a church, fed and watered with regular doses of the means of grace (preaching & sacraments), can not help but to bear fruit. If a Christian is not bearing fruit (doing good works), it's a sign that the conditions she's in need immediate improvement.
FRUIT PRODUCTION IS PASSIVE: Technically, vines do not produce fruit, rather they bear fruit, which is the word John uses. As we saw in the last paragraph, the grape vine doesn't do something to make grapes, rather the grapes passively come naturally. You are not called to produce good works. That's what the Pharisees were trying to do: they were actively trying to fabricate works that made them look better. Rather, you've been called to passively bear the fruit of good works. In other words, take care to make sure you're planted in the right conditions and being regularly fed with God's Word, and then the fruit will come quite naturally (although often you won't even notice - see the parable of the sheep and goats).
DON'T BE SO SHOCKED: Many of us are old enough to remember better times in our country, times where most people were at least familiar with godly values. We should be actively working in our communities to restore these values, but at the same time, remember that the normal condition of things is for the world to hate Christians; in fact, Jesus promises this in v18-25. As you see more and more evidence of this in our society, be reminded not only of Jesus' teaching that the world will hate you, but also of His assurance that the Holy Spirit will enable you to hold to your testimony of who Jesus is no matter how the world hates you for it (v26-27).
Follow the AAA Prayer Pattern:
ACKNOWLEDGE WHO GOD IS: God the Father, who loves you (v9)
ALIGN YOUR LIFE WITH GOD'S WILL: Pray that you will keep yourself in good growing conditions, fed and watered by God's Word, so that you will go and bear fruit that will last (v16)
ASK GOD FOR WHAT YOU NEED: