Paul continued his testimony by introducing the supernatural part of his story.

As I was on the road, approaching Damascus about noon, a very bright light from heaven suddenly shone down around me. 7  I fell to the ground and heard a voice saying to me, ‘Saul, Saul, why are you persecuting me?’ 8  “‘Who are you, lord?’ I asked. “And the voice replied, ‘I am Jesus the Nazarene, the one you are persecuting.’ Acts 22:6-8 (NLT)  

Our testimony is about how God intersected our lives.

Unless God intervenes, all of us are headed for hell. We don’t need any help to pull that off. That was certainly the case with Paul. He was “hell bent” on persecuting Christians in an attempt to stamp out what had become known as “the Way.” As the chief enemy of the faith, he was perhaps the most unlikely of all people to have an encounter with the risen Christ, which is exactly the point. Later he wrote the following.

This is a trustworthy saying, and everyone should accept it: “Christ Jesus came into the world to save sinners”—and I am the worst of them all. 16  But God had mercy on me so that Christ Jesus could use me as a prime example of his great patience with even the worst sinners. Then others will realize that they, too, can believe in him and receive eternal life. 1 Timothy 1:15-16 (NLT) 

A good testimony invites people to consider that God is real, cares about us, and can communicate effectively.

Most people are unaware that this sort of thing can happen, and, even if they know it can, they do not believe it will happen to them personally.

If we convince our hearers that they are candidates for divine intervention, just as we were, perhaps they will seek God for themselves.

God does not turn away any sincere seeker. If our listeners will honestly turn to God and ask him for help, the Lord will not turn his back on them.

However, those the Father has given me will come to me, and I will never reject them. John 6:37 (NLT)