What does Matthew 10:26 mean?

Jesus has been warning His disciples of great persecution that will happen to them as they represent Him and His teaching in the world. After all, a servant should expect to get the same as his master. Since Jesus has been lied about and will be persecuted, the disciples should expect the same (Matthew 10:24–25). He has referred to one source of that persecution: the Jewish religious leaders. They have already called Jesus Satan (Matthew 9:34; 12:24), He told them. How much more will they malign and mistreat His disciples when they begin declaring that Jesus is, in truth, the Son of God?

Now Christ insists that the apostle's response to the coming persecution must not be fear. Jesus is not warning them so they can evade persecution. He is warning them so they can endure persecution: to be ready for it and keep going. In the end, Christ-followers will be proved right and the true motives of Jesus' opponents will be brought to light. Everything that is "covered" and "hidden" will become known. In the very end, all will agree that Jesus is Lord, the Son of God, the Messiah (Philippians 2:9–11). The Jewish religious leaders may label Jesus' disciples as heretics and may even kill them for it, but they will be proved right and faithful before everyone.