"And when he went forth to land, there met him out of the city a certain man, which had devils long time, and ware no clothes, neither abode in any house, but in the tombs. When he saw Jesus, he cried out, and fell down before him, and with a loud voice said, What have I to do with thee, Jesus, thou Son of God most high? I beseech thee, torment me not.
"(For he had commanded the unclean spirit to come out of the man. For oftentimes it had caught him: and he was kept bound with chains and in fetters; and he brake the bands, and was driven of the devil into the wilderness.)
"And Jesus asked him, saying, What is thy name? And he said, Legion: because many devils were entered into him. And they besought him that he would not command them to go out into the deep. And there was there an herd of many swine feeding on the mountain: and they besought him that he would suffer them to enter into them. And he suffered them.
"Then went the devils out of the man, and entered into the swine: and the herd ran violently down a steep place into the lake, and were choked. When they that fed them saw what was done, they fled, and went and told it in the city and in the country."
(Luke 8:27-34 KJV)
"And they come to Jesus, and see him that was possessed with the devil, and had the legion, sitting, and clothed, and in his right mind: and they were afraid.
"And they that saw it told them how it befell to him that was possessed with the devil, and also concerning the swine. And they began to pray him to depart out of their coasts.
"And when he was come into the ship, he that had been possessed with the devil prayed him that he might be with him. Howbeit Jesus suffered him not, but saith unto him, Go home to thy friends, and tell them how great things the Lord hath done for thee, and hath had compassion on thee. And he departed, and began to publish in Decapolis how great things Jesus had done for him: and all men did marvel."
(Mark 5:15-20 KJV)
In this story of the demoniac, we see the basis of true witnessing: it is the sharing of one's personal testimony or experience. Just as in the legislative system, witnesses tell the story from their point of view, in their own words -- as they saw it, heard it, felt it. It's their experience altogether.
The the best thing about such a testimony is that no one can argue about it. No audience can say that the witness has falsified their message to their own advantage, because they were not there and did not experience it; only the witness himself can say, "I lied." And, on the other hand, the speaker can not say that all must have his experience in order to have any real experience at all; each person endures different circumstances and has different stories.
A true witness cannot be countered. No one can tell me that I am wrong about my experience. But if my my witness is true and penetrating, then others might be led to search for themselves.You can only experience something for yourself. "O taste and see that the Lord is good..." (Psalm 34:8).
We see this very thing illustrated in John 4, with the woman of Samaria. After her encounter with Jesus, she ran back to the city with this testimony: "Come, see a man, which told me all things that ever I did: is not this the Christ?"
"Come see what I saw! You evaluate it for yourself." She had met someone who read her life story like an open book; and by that she came to a conclusion. Now she says, "Come meet this guy, and find out what experience you have!"
As it turned out, the people did have an experience with Jesus; so much so that they said to the woman who had led them there, "Now we believe, not because of thy saying: for we have heard him ourselves, and know that this is indeed the Christ, the Saviour of the world." We have heard Him for ourselves. We now have our own experience with Him.
Now that's a true witness!
As witnesses for Christ, our personal testimonies build on each other. One person's testimony confirms another person's testimony. We form this collection or scrapbook of experiences in advocate of Christ and Him crucified.
"And they overcame him [the "accuser of our brethren"] by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death" (Revelation 12:11).