What does John 16:3 mean?
Jesus is warning His followers that persecution will come (John 16:1), and it may become brutally violent (John 16:2). The reason for giving these dire predictions is to strengthen faith. Believers should recognize that hardship is not something which catches God by surprise. Rather, this is exactly how He told us things would play out. In the previous verse, Christ pointed out that some of the most brutal oppression will come from those who think murdering Christians is an act of good!Clearly, as stated here, those who assault believers do so because they, themselves, have no relationship with God. Earlier, Jesus pointed out that love for one another was a primary sign of faith (John 13:34–35). Here, we see the other side of that: hateful persecution of believers is a clear sign of someone—or a culture—disconnected from saving faith. Those who hate and harm believers do so because they are deeply, spiritually opposed to God and to His Son (1 Peter 2:3–4; John 15:18).
John 16:1–4 completes a thought Jesus began at the end of chapter 15. He has been warning His disciples about the persecution they will face, due to their association with Him. His intention is not to frighten, but to reassure. The message seems dire: enemies will ostracize and even kill followers of Christ. However, knowing this was something God anticipated should give believers confidence that everything is under His control.
Throughout His teaching in the Last Supper (John 13:1–5), Jesus has often brought up the fact that He's giving His followers advance warnings (John 13:19; 14:25). His intent is to provide encouragement—persecution as a result of their faith is inevitable. In keeping with that reassurance, Jesus again promises the coming of the Holy Spirit. He explains that after a time of deep sorrow, His followers will experience great joy and clarity. This concludes with a beloved promise that Christ has "overcome the world."