Any time the people of God compromise, their testimony is either greatly harmed or destroyed completely. Many Christians today have mingled with the world and have ruined their testimony. There are also churches today that have taken a weak and feeble stand against worldliness and sin, thus destroying their power with God. God's plan for the church and the individual Christian is to reach the world, without mingling in its sin. One must never partake of the sins of the world in order to be a friend to the world.
Fear usually leads to compromise.
Many times Christians give in to protect themselves. Moses warns the people not to be afraid of the enemy, because God will be with them and given them the victory. That same promise is ours today. No matter what may befall us, God will not leave us or forsake us. If you are born-again, you are a child of God and He will never forsake His own.