Telling a person how you came to the Lord can change their life. Today, I got to tell a coworker about how I came to the Lord. Do I know for a fact it will change his life, no. However, if there is even the slightest chance, then it was worth it.
Mark 5:19 New International Version (NIV)
19 Jesus did not let him, but said, “Go home to your own people and tell them how much the Lord has done for you, and how he has had mercy on you.”
I realize it is not everyday that the opportunity presents its self to allow you to express to another what the Lord has done for you, but if you look for those chances, they will be there. There is nothing that the Lord does not control, you just have to open your heart and be ready when that rare chance does exist.
I pray that when that opportunity does exist for you to give your testimony to another, that you not only see it, but also have the courage to tell it.