What Christ is not saying is, stop yourself fearing those who persecute you and who may try to kill you, but quake before him who can send you to hell. We believe in final perseverance; God is not going to change his mind about who he loves and lash out and destroy them.
If you fear to witness – and only a minority do not – then don’t try to quell your fear: you cannot. Instead, redirect it. Christ is teaching his disciples how to cope with the fear of death. He recognises that that fear is a reality, but the Christian must be prepared to love the Lord more than he loves his own life, and to be willing to lay down his life for the Lord if called upon to do so. The power of the world to hurt us is limited. Set that power against the far greater power of God to hurt those who do not trust in him. It is easy to see which is to be preferred. Christ requires his disciples to lay down their lives for him, but he has promised he will never forsake us. These words are solemn and deep, but they have been of comfort to many who have found themselves facing the powerful dilemma of whether to choose faithfulness to the Lord or the preservation of their own lives.