Agricultural illustrations are all over the New Testament. It's to our detriment that we are so far removed from growing things that it has become difficult for us to grasp these. It's worth your time to read up a bit on how gardening and growing plants. You can find some good ones that weave both agriculture and Biblical interpretation, though keep in mind that books like The Trellis and the Vine move beyond facts and into opinions of the meaning of Scripture.
Which does not automatically make the opinions wrong. Just opinions--though well-researched opinions are very, very helpful.
Now, Jesus goes on to teach about remaining in fellowship with Him. He explains to the disciples that trouble is coming to them. They will face the people who have been their family, their nation, and those old friends will attack them. 16:2 brings out that those who do this will believe they are serving God by killing those who follow Christ.
Let that sink in: as a follower of Jesus, everything you do should be done because you are serving God. Yet, some of those who attack you do so believing they are doing the same thing. Which is why persecution comes with so much intensity: it's done as worship to a false view of God.
The focus for us, then, is not to attack the people that bring the difficulty but to show them a true view of Jesus. That may be harder than fighting back. But it is what we are called to do.