What does John 17:15 mean?

Among the more challenging aspects of biblical faith is that God does not promise to take believers out of persecution or hardship. Rather, merely obeying Christ (John 14:15) can be enough to earn hatred from the unbelieving world (John 17:14; 1 Peter 4:4). God assures us He will be with believers in their hardship (John 16:33), and what they experience is part of their preparation for something greater (Romans 8:18, 28).

In keeping with that theme, Jesus reiterates that His prayer is not for God to remove Christians from the world (1 Corinthians 5:9–10). Rather, He prays for the durability of their faith (Hebrews 3:6; John 16:1–4). The only way for believers to reach others with the gospel (Matthew 28:19) is to demonstrate Christian truth in our own lives (Matthew 5:13–16; 1 Peter 3:15). This part of Jesus' High Priestly Prayer is most immediately about His closest disciples (Matthew 10:1–4); other than Judas (John 17:12), these men will carry on the teachings of Jesus after His death and resurrection. However, modern Christians (John 17:20) are also "in the world," yet commanded not to be "of the world" (John 17:14).