On a Dangerous Mission but do not Fear
Although the Good News about Jesus is the most wonderful message in the world, many people hate the message and the Saviour. As in many conflict situations, fear plays a large part in determining the outcome: propaganda and criticism attempt to demoralise the opposition until they lose their will to continue. Jesus told His disciples to expect antagonism but not to be afraid; because in the end, the gospel-bearers will be proved right.
Although the world is filled with a mixture of truth and lies, and people believe what is convenient to them, it will not always be that way. A Day is coming when the truth of everything will be exposed; and the gospel with all its wonderful truths about Jesus will be acknowledged to be right, even by those who hated Him (Revelation 1:7). They might kill the bodies of Jesus and His disciples, but they can never destroy their souls.
Therefore, the trainee apostles were urged not to hold back in speaking the truth about Jesus. What they had heard from Him was not to be kept secret, but should be broadcast (in those days the flat roofs of ordinary houses made excellent pulpits). Their evening discussions with the Lord should fuel their morning conversations with their neighbours. Three times in these verses He tells them not to be afraid of gospel-haters ... but keep on gospelling. The only person to fear is the Lord who had appointed them to take the message to the world: they must not frustrate His purpose to save many people from hell.
Fear is one of Satan's most potent weapons. Naturally, we love approval and hate criticism. Therefore we modify what we do and say in order to maximise approval and minimise criticism. But whose approval should we seek? Those who can kill our body or the One who can condemn our soul? The apostles understood what Jesus was saying and did not shrink back (Acts 4:18-20). What about You?