No, I'm not talking about a court of law here. This is a special use of the word "Testimony" which deals specifically about someone's close encounter of the G-d kind. It derives from the fact that people who are followers of Yeshua are called to be his "witnesses." The job of a witness is to give testimony. This is mine.
Back in the dark ages of the late 70's, I was heavily into what later became known as the "New Age Movement." It's an eclectic collection of everything from ESP to Tarot cards. I didn't think there was anything wrong with it, since I wasn't really hurting anyone.
In 1978, I graduated college in the spring and got married in the fall. Everything seemed to be going well, but that winter, I discovered a great many food sensitivities, and began losing weight. I dropped from 150 pounds down to about 120 pounds in only a of couple months. The doctors were concerned, and were talking about checking me into a hospital for some tests.
A little while after that, my wife and I were going out to a movie at a nearby shopping mall. We got there early, so we walked through a bookstore. While we were in there, I picked up a copy of Satan is Alive and Well on Planet Earth by Hal Lindsey. It seemed to be talking about the stuff I was into, and I thought Satan was "bad," too. Interestingly, there was a spiritual battle going on of which I was unaware, since I put the book back at one point, then went ahead and bought it, thinking I could read it if I did wind up in the hospital for testing.
After that, on Easter weekend, 1979, my wife and I were planning to attend services with her family at a mainline Protestant church. We never made it. I awoke with terrible pains in my midsection. We called my doctor, and headed for the emergency room. Since I had all the mysterious problems with weight loss, they decided to admit me.
The prognosis didn't look good. The doctors were talking about all sorts of serious ailments. I was afraid, but tried the best I could to deal with it. I had my wife bring me the Hal Lindsey book, and started reading it there in the hospital.
What an eye-opener! The book quoted Deuteronomy 18 (this from the New American Standard version):
Deu 18:9 "When you enter the land which the LORD your God gives you, you shall not learn to imitate the detestable things of those nations.
Deu 18:10 "There shall not be found among you anyone who makes his son or his daughter pass through the fire, one who uses divination, one who practices witchcraft, or one who interprets omens, or a sorcerer,
Deu 18:11 or one who casts a spell, or a medium, or a spiritist, or one who calls up the dead.
Deu 18:12 "For whoever does these things is detestable to the LORD; and because of these detestable things the LORD your God will drive them out before you.
Deu 18:13 "You shall be blameless before the LORD your God.
Deu 18:14 "For those nations, which you shall dispossess, listen to those who practice witchcraft and to diviners, but as for you, the LORD your God has not allowed you to do so.
Deu 18:15 "The LORD your God will raise up for you a prophet like me from among you, from your countrymen, you shall listen to him.
Whoops. I had done many of those things, and G-d wasn't pleased. In fact, I was "detestable to the LORD." There was nothing that I, myself could do to remedy the situation. If someone commits a crime (say, murder), he can't make up for it by living a law-abiding life, no matter how long it lasts. Nope. I needed someone to pay for my crime on my behalf.
As it is written in the book of Isaiah, chapter 53:
Isa 53:4 Surely our griefs He Himself bore, And our sorrows He carried; Yet we ourselves esteemed Him stricken, Smitten of God, and afflicted.
Isa 53:5 But He was pierced through for our transgressions, He was crushed for our iniquities; The chastening for our well-being fell upon Him, And by His scourging we are healed.
Isa 53:6 All of us like sheep have gone astray, Each of us has turned to his own way; But the LORD has caused the iniquity of us all To fall on Him.
That was the answer I needed. There, in the hospital room, I prayed like I had never prayed before, throwing myself upon G-d's grace and mercy as demonstrated by the death of Yeshua on my behalf. Anything he would have me do, I would do. My entire life could not pay for what he had done for me, but it is his to do with as he pleases.
Oh - and all those weird physical problems that landed me in the hospital in the first place? After I received the L-rd, they suddenly went away. Fancy that.
Since I was saved in isolation via a book, G-d took special care with me to disciple me and to get me into a group of solid believers who encouraged me and taught me what it takes to live a life pleasing to Him. He called me into leading a house church for many years as a deacon of a Bible Church in the area, then to become an elder of a Messianic Congregation, then to be ordained as a pastor and to lead B'nai Avraham. It hasn't always been easy, but it's always been exciting and satisfying.