Some time ago, I heard a sermon illustration using the following historical event. I decided it also had pertinent application to this area of evangelism.
Almost 170 years before Christ's birth, a king by the name of Antiochus IV found himself heavily involved in a war of conquest against the king of Egypt. He was nearly victorious; all of Egypt had fallen to his army except for the city of Alexandria. Antiochus placed himself at the head of an army and marched against the city. On the road, however, he was stopped and confronted by a man named Laenas, an aged Roman ambassador. The Roman senate, concerned about Antiochus' growing power, sent the ambassador to give Antiochus' an ultimatum; withdraw from Egypt or face war against Rome. In an attempt to buy himself time, Antiochus told the ambassador that he would discuss the decision with his counselors. The Roman envoy boldly strode forward and drew a circle around the king. The ambassador told Antiochus that if he stepped out of the circle without agreeing to withdraw his armies, Rome would declare war.
On one side stood a king, backed by a mighty and numerous army. On the other, a solitary old man. What was the result? The king backed down before the ambassador and agreed to withdraw. Why would a sovereign supported by a host of loyal followers surrender his will to that of an aged ambassador? Because Antiochus' feared the power of Rome. He feared the power the ambassador represented.
The field of evangelism is a very literal battlefield. Ephesians 6:11-12 says "Put on the whole armor of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places." Christians fight, not in a physical contest, but in a spiritual war for the souls of men. Those redeemed by the blood of the Lamb are arrayed on one side of this field. On the opposing side, marshalled against us are the world, the ungodly culture and unbelievers; the flesh, the inherent sin nature that still resists the work of God in our lives; and the devil, Satan and all his host. With governments, media, and popular feeling turned oftentimes against us, our efforts to reach "lives for whom [Christ] died" seems hopeless indeed...until the force supporting us is revealed.
"Now then we are ambassadors for Christ..." (2 Cor. 5:20) Such are the words of Paul as he unveils the power by which we fight. We do not fight alone and by our own strength; we are sent as representatives, fully empowered, equipped, and enabled by God to do what He has called us to accomplish. The result? "Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world." We fight with power unseen, yet so potent that victory is assured.