What does Matthew 10:27 mean?
Jesus is warning His disciples about the persecution that will come to them when they preach His message to the world (Matthew 10:22–26). The Jewish religious leaders, for one, will call them heretics for saying that Jesus is the Messiah, the Son of God. They have already said that Jesus' undeniable power comes from Satan (Matthew 9:34).Jesus doesn't want His followers to respond to this persecution in misplaced fear—He wants them to expect it, but to do so with confidence. He has promised them they will be vindicated for preaching the truth about Him. Every hidden and covered thing about Him will come to light, and all will know that they were faithful to the truth (Philippians 2:9–11).
Now He tells them to be the ones to start declaring that truth. Jesus has not fully revealed to Israel and the world that He is the Christ, the Son of the living God. In fact, He has told many of the people He has healed not to tell anyone about what happened in order to keep that truth from being fully understood until the time was right. Instead, He has revealed these truths to His disciples about things they likely will not understand until after His resurrection from the dead.
When the time comes, though, Jesus wants His disciples to broadcast those truths far and wide in a fully public way. He wants them to proclaim the truth that He is the Messiah, the Son of God, from the housetops. The flat rooftops of Palestinian houses provided excellent platforms for speakers to large groups of people. The disciples' work would include declaring previously hidden truths.